A 37-year-old male with thalassaemia intermedia (alpha and beta) had undergone cholecystectomy and splenectomy in childhood, but had received no regular transfusions or medications since his haemoglobin (around 8 g/dL) and ferritin levels (approximately 4300 pmol/L) remained stable. He had multiple extramedullary haematopoietic (EMH) lesions in the bilateral paraspinal regions, evident on previous magnetic resonance imaging (Fig 1a). Following a recent viral infection in January 2025 with nasopharyngeal swab testing positive for influenza A and B and respiratory syncytial virus, he reported back pain and dark-coloured urine. Blood tests revealed a drop in haemoglobin level to 4.9 g/dL. The working diagnosis was haemolysis precipitated by infection. An initial computed tomography (CT) of the thorax revealed bilateral pleural effusions and the known EMH, but no evidence of haemorrhage (Fig 1b).

A few days later, the patient developed sudden chest pain, with tachycardia and hypotension (blood pressure: 82/43 mm Hg). Urgent CT of the thorax revealed a left haemothorax and blood products adjacent to the largest paraspinal EMH in the left lower hemithorax, along with new intralesional pseudoaneurysms and multiple dysplastic vessels, indicative of active bleeding (Fig 1c-e). A left chest drain was placed, yielding 1.3 L of heavily blood-stained fluid. He was referred to interventional radiologists for urgent embolisation to control the bleeding.

Urgent embolisation was performed under local anaesthesia. A 5-Fr Mikaelsson catheter (Merit Medical, South Jordan [UT], United States) was inserted via transfemoral access to catheterise the left lower intercostal arteries. Digital subtraction angiography revealed abnormal, tortuous vessels with small pseudoaneurysms arising from the left 10th and 11th intercostal arteries and supplying the dominant left lower thoracic EMH (Fig 2a and b). Selective cannulation of these arteries was performed using a 2.1-Fr Maestro microcatheter (Merit Medical). Superselective embolisation was then performed at several branches using a combination of 700-900 μm Embosphere (Merit Medical) and 710-1000 μm EGgel (ENGAIN, Hwaseong-si, South Korea). A postprocedural angiogram showed successful devascularisation of the lesion and obliteration of the pseudoaneurysms (Fig 2c and d).

Following the procedure, the patient’s vital signs normalised and there were no neurological deficits. His haemoglobin level stabilised at 7 to 8 g/dL and chest drain was later removed due to minimal output. Follow-up CT 2 weeks later showed a reduction in the left haemothorax and decreased vascularity of the left lower thoracic EMH (Fig 1f). The patient was discharged and remains asymptomatic to date, with no clinical evidence of re-bleeding.

Extramedullary haematopoiesis refers to the compensatory production of blood cells outside of the bone marrow, typically occurring in patients with insufficient bone marrow function, such as those with thalassaemia. Diagnosis can be made clinically and radiologically, especially when the lesions are multifocal or bilateral, exhibiting characteristic iron deposition or fatty replacement on imaging.1 Paraspinal EMH can lead to complications such as spinal cord compression or, rarely, haemothorax due to rupture and bleeding into the pleural cavity. In our patient, it was hypothesised that haemolysis from the recent infection increased the demand for haematopoiesis, stimulating the existing EMH to recruit additional blood vessels under stress. This angiogenesis ultimately led to intralesional bleeding, pseudoaneurysm formation and haemothorax.

There are no established evidence-based guidelines for the treatment of EMH. Management depends on lesion size and location, as well as the patient’s clinical condition.2 In uncomplicated cases, hypertransfusions aimed at correcting anaemia and reducing haematopoietic demand can shrink EMH lesions. Radiotherapy may also be used, as haematopoietic tissue is radiosensitive and tends to regress following irradiation. Nonetheless, when complications such as haemorrhage arise, more urgent intervention is needed. Thoracotomy with surgical excision has traditionally been performed, but emergency surgery carries higher risks of bleeding and other complications.3 Embolisation has emerged as a mainstay treatment for many haemorrhagic conditions due to its versatility and precision. Our case demonstrated its viability in EMH-related haemorrhage, enabling accurate identification of bleeding vessels and prompt haemostasis while minimising the risks of more invasive surgery.

To ensure a safe and effective embolisation, meticulous planning and identification of the target vessels are essential, including superselective cannulation to prevent non-target embolisation. Spinal cord feeders can arise from intercostal arteries and are identified by their characteristic hairpin appearance as they course medially to the vertebral pedicle.4 In particular, the artery of Adamkiewicz, the largest anterior medullary branch to the anterior spinal artery, commonly arises at left-sided T9 to T12 levels. Reflux into these arteries can lead to spinal cord ischaemia. A balance must be struck between complete devascularisation of the lesion and the risk of non-target embolisation. Larger embolic agents, such as particles larger than 350 μm, are theoretically safer as they are too large to enter the small-calibre spinal arteries. Embolic agents should be injected slowly under fluoroscopic guidance, with close monitoring for any interval appearance of spinal artery supply or reflux.

The choice of embolic agents is important and depends on factors such as the location of target vessels, proximity to vital structures, and operator experience. In our case, a combination of permanent and temporary particulates was used to achieve haemostasis. Embospheres are non-absorbable, calibrated microspheres available in various sizes. The 700-900 μm size was chosen to prevent entry into spinal arteries. These provide a long-term embolic effect with predictable delivery.5 EGgel (710-1000 μm), a porcine-derived gelatin microparticle, was used for further proximal embolisation. It offers temporary embolisation, complementing Embospheres by preventing vessel recanalisation under high intraluminal pressure.

Haemorrhage associated with EMH is a critical condition requiring prompt and effective intervention. Embolisation can be life-saving in such cases. Although further studies are needed to assess long-term outcomes, embolisation should be considered part of the multidisciplinary management of patients with EMH.

Concept or design: KH Chu, L Xu.
Acquisition of data: KH Chu, L Xu.
Analysis or interpretation of data: KH Chu, L Xu.
Drafting of the manuscript: KH Chu, L Xu.
Critical revision of the manuscript for important intellectual content: All authors.

All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

This study was approved by the Central Institutional Review Board of Hospital Authority, Hong Kong (Ref No.: CIRB-2025-064-2). The patient provided written informed consent for all treatments and procedures, and for publication of the case report, including the accompanying clinical images.

1. Hughes M. Rheumatic manifestations of haemoglobinopathies. Curr Rheumatol Rep 2018;20:61. Crossref

2. Gupta S, Krishnan AS, Singh J, Gupta A, Gupta M. Clinicopathological characteristics and management of extramedullary hematopoiesis: a review. Pediatr Hematol Oncol J 2022;7:182-6. Crossref

3. Pornsuriyasak P, Suwatanapongched T, Wangsuppasawad N, Ngodngamthaweesuk M, Angchaisuksiri P. Massive hemothorax in a beta-thalassemic patient due to spontaneous rupture of extramedullary hematopoietic masses: diagnosis and successful treatment. Respir Care 2006;51:272-6.

4. Papalexis N, Peta G, Gasbarrini A, Miceli M, Spinnato P, Facchini G. Unraveling the enigma of Adamkiewicz: exploring the prevalence, anatomical variability, and clinical impact in spinal embolization procedures for bone metastases. Acta Radiol 2023;64:2908-14. Crossref

5. Wang CY, Hu J, Sheth RA, Oklu R. Emerging embolic agents in endovascular embolization: an overview. Prog Biomed Eng (Bristol) 2020;2:012003. Crossref

A 60-year-old man was admitted as an emergency to North District Hospital in March 2024 with a 1-day history of progressive abdominal distension. He also reported colicky central abdominal pain without radiation, vomiting of clear fluid, and no bowel movements for 2 days. He was a chronic smoker and social drinker but past medical history was unremarkable, except for bilateral renal stones treated with extracorporeal shock wave lithotripsy in 1998 and 2003.

His vital signs on admission were temperature 36.6°C, heart rate 104 bpm, blood pressure 157/99 mm Hg, and respiratory rate of 16. Physical examination revealed a mildly distended abdomen without peritoneal signs. Laboratory tests were abnormal with a white blood cell count of 21.0×10³/μL and lactate of 4.9 mmol/L. Abdominal X-ray showed prominent bowel loops in the central abdomen. Computed tomography revealed a distended gallbladder, oedematous gallbladder wall thickening and pericholecystic inflammatory fat stranding without gallstones; the caecum and a segment of terminal ileum were prominently dilated, measuring up to 8.4 cm and 2.8 cm, respectively, with a gradual transition zone identified between the caecum and the ascending colon (Fig 1). Initial radiology suggested acute cholecystitis and faecal impaction. However, after further clarification and in the absence of any mesenteric rotation or twisting, a diagnosis of caecal volvulus (bascule type) could not be made.

Antibiotics were started immediately. Emergency surgery for cholecystectomy and evaluation of the caecum was offered. Laparoscopy revealed a grossly distended caecum with congestion of part of the caecal wall, which appeared to fold anteromedially, creating a closed-loop obstruction (Fig 2). The gallbladder was inflamed. Laparoscopy proceeded to open surgery, and a right hemicolectomy with primary ileo-colic anastomosis and cholecystectomy were performed. A 3-cm gallstone was found inside the gallbladder.

Pathological examination of the right hemicolectomy specimen revealed marked thinning of the intestinal wall (1 mm thick) with features consistent with volvulus. The overlying mucosa appeared dusky. Microscopically, there were features of early-stage ischaemia with sloughing of the overlying epithelium, submucosal oedema, and purulent fibrinous exudate over the serosal surface. Gallbladder pathology confirmed acute gangrenous cholecystitis.

Caecal volvulus accounts for 1% of intestinal obstruction cases, with an incidence of 2.8 to 7.1 per million people per year.1 It is classified according to geometry: the caecal bascule is the rarest form, designated as type III caecal volvulus, accounting for 20% of all caecal volvuli.1 A systematic review in 2018 reported only 26 cases in the literature, with a median age of 55 years and a male-to-female ratio of 14:12.2 It involves anterior-superior folding of the caecum without axial twisting, leading to obstruction of the ascending colon.1 If the ileocaecal valve is competent, bowel dilatation is confined to the caecum, forming a closed-loop obstruction. In the absence of torsion, diagnosis via cross-sectional imaging is more challenging. Delayed diagnosis and treatment may result in bowel ischaemia, gangrene, and perforation.

The caecum is normally a secondary retroperitoneal and immobile structure. However, it can become mobile due to congenital or acquired factors, predisposing it to volvulus. Common risk factors include previous abdominal surgery, high fibre intake, chronic constipation, and distal bowel obstruction.

Clinically, caecal volvulus presents similarly to small bowel obstruction. Cardinal symptoms include nausea, vomiting (30%), abdominal pain (61%), and abdominal distension (84%).2 Caecal bascule may manifest with milder symptoms and reduced risk of ischaemia, as there is less mesenteric torsion and the caecum may return to its anatomical position.

Although computed tomography is the initial diagnostic tool of choice, with a reported sensitivity of 61%, some cases are diagnosed only during exploratory laparotomy.2 The classic ‘whirl sign’, seen in types I and II caecal volvulus, is absent in caecal bascule. Instead, the distended caecum folds anteriorly without torsion and typically located in the central abdomen.3 The transition zone lies between the ascending colon and caecum.

In our patient, diagnosis of caecal bascule was difficult, likely due to the rarity of the condition. With hindsight, the appendiceal orifice lay medial and superior to the terminal ileum, offering indirect evidence of anterior-superior folding to the caecum. A grossly distended caecum in isolation should raise suspicion of caecal volvulus. Examining the relative positions of the appendix and terminal ileum may provide diagnostic clues.

Prompt surgical intervention is often recommended due to the high risk of perforation. Non-operative management has a success rate as low as 3.8%, and endoscopic treatment success is reported at up to 30%, much lower than 70% to 95% in sigmoid volvulus.3 Surgical options depend on bowel viability and intraoperative stability. Right hemicolectomy with primary ileo-colic anastomosis is the treatment of choice with the lowest recurrence risk. Alternatives such as ileocecal resection with colopexy of the right colon remnant2 and derotation with caecopexy or caecostomy have been reported.2 3

Acute cholecystitis is rarely associated with caecal volvulus, with the first report in 2013.4 It was believed that the right colon adhered to the inflamed gallbladder formed part of an inflammatory phlegmon, acting as a pivot for caecal rotation. However, this phenomenon was not observed intraoperatively in our case.

To the best of our knowledge, this is the second reported case of caecal bascule in Hong Kong.5 This case highlights the diagnostic challenge for this rare condition. A high index of clinical suspicion is needed for timely diagnosis. Greater awareness among healthcare professionals may help prevent serious outcomes from this potentially life-threatening presentation.

Concept or design: Both authors.
Acquisition of data: Both authors.
Analysis or interpretation of data: HW Ip.
Drafting of the manuscript: Both authors.
Critical revision of the manuscript for important intellectual content: HW Ip.

Both authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

Both authors have disclosed no conflicts of interest.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

The patient was treated in accordance with the Declaration of Helsinki. Written consent was obtained from the patient for all treatments and procedures, and publication of the case report, including the accompanying clinical images.

1. Delabrousse E, Sarliève P, Sailley N, Aubry S, Kastler BA. Cecal volvulus: CT findings and correlation with pathophysiology. Emerg Radiol 2007;14:411-5. Crossref

2. Lung BE, Yelika SB, Murthy AS, Gachabayov M, Denoya P. Cecal bascule: a systematic review of the literature. Tech Coloproctol 2018;22:75-80. Crossref

3. Takahashi M, Ando Y, Kochi S, et al. Three surgical cases of cecal volvulus. Cureus 2024;16:e72794. Crossref

4. Anjum GA, Jaberansari S, Habeeb K. Caecal volvulus: a consequence of acute cholecystitis. BMJ Case Rep 2013;2013:bcr2013009705. Crossref

5. Kim YI, Han SK, Min MK, Park SW, Yeom SR. Improvement of a cecal bascule by supportive care. Hong Kong J Emerg Med 2017;25:102490791774814. Crossref

A 42-year-old woman was admitted to Weifang Second People’s Hospital on 20 June 2024 following an incidental finding of a pulmonary nodule (21 × 27 mm²) during a routine physical examination 1 year previously. Although serial imaging over the following year showed stable size and morphology, suggesting a benign nature, malignancy remained possible. The patient had no significant medical, family, or psychosocial history, and denied tobacco and alcohol use. Preoperative evaluation included fine-needle aspiration cytology, which revealed spindle cells with lymphoplasmacytic infiltration. Contrast-enhanced chest computed tomography demonstrated a lobulated left upper lobe nodule with heterogeneous enhancement and partial bronchial obstruction (Fig 1). Magnetic resonance imaging of the brain and abdominal ultrasound showed no metastasis. Based on the above investigations and considering the patient’s financial circumstances, a positron emission tomography scan was not performed. Tumour marker levels were within the normal range—neuron-specific enolase: 13.06 ng/mL, carbohydrate antigen 19-9: 9.76 U/mL, carcinoembryonic antigen: 1.54 ng/mL, cytokeratin 19 fragment: 1.23 ng/mL, and squamous cell carcinoma antigen: 0.51 ng/mL. Thoracoscopic left upper lobectomy was performed on 22 June 2024. Histopathology revealed proliferating spindle myofibroblasts/fibroblasts with lymphoplasmacytic infiltration and focal mucin deposition (Fig 2). Immunohistochemistry confirmed inflammatory myofibroblastic tumour (IMT): positive for cytokeratin, vimentin, smooth muscle actin (SMA), and epithelial membrane antigen; STAT6 (signal transducer and activator of transcription 6) negative with a Ki-67 index of 30%. The patient recovered well, with no recurrence at 3-month follow-up, although long-term surveillance was recommended.

Inflammatory myofibroblastic tumour, originally termed inflammatory pseudotumour (IPT) in 1939, has been reclassified through molecular insights from a reactive proliferation to a true neoplasm.1 Although IPT remains a non-neoplastic inflammatory lesion with regression potential, IMT is now defined as a clonal neoplasm composed of myofibroblastic spindle cells within a plasma cell/lymphocyte/eosinophil-rich stroma. This distinction is crucial clinically since IMT exhibits local invasiveness and recurrence risk, unlike IPT’s benign course.2

Inflammatory myofibroblastic tumour is a rare mesenchymal neoplasm that primarily affects children and young adults, with lower incidence in adults.3 Its broad anatomical distribution most commonly involves the lungs (0.7% of pulmonary tumours)4 and the abdomen/mesentery/retroperitoneum; rare sites include the oesophagus, cardiac chambers, and adrenal glands. As a borderline malignancy, recurrence rates differ by site (pulmonary 2% vs extrapulmonary 25%), with less than 5% risk of distant metastasis.5 Symptoms vary anatomically: pulmonary cases may present with cough or haemoptysis (including incidental detection), abdominal lesions may cause pain or obstruction, while systemic symptoms include fever and weight loss. Pulmonary IMTs, as observed in our patient, may present with cough, atypical chest pain, haemoptysis, or dyspnoea, although incidental detection during routine health screening, as in our case, is not uncommon.

The non-specific radiological features of IMT pose significant diagnostic challenges, necessitating histopathological confirmation. In our patient, the nodule was identified during a routine physical examination 1 year prior to admission, and serial imaging demonstrated stable lesion size. This supported a benign nature but did not entirely exclude malignancy. Although minimally invasive techniques such as fine-needle aspiration biopsy and bronchoscopic sampling are often attempted, these methods frequently yield insufficient tissue for definitive diagnosis. Complete surgical resection therefore remains the gold standard for both diagnostic confirmation and therapeutic intervention.

Histopathological examination typically reveals spindle-shaped myofibroblastic proliferation within variable stromal matrices (myxoid, collagenous, or calcified patterns), accompanied by a polymorphic inflammatory infiltrate. In our patient, the histopathological features were consistent with IMT, showing proliferating spindle-shaped myofibroblasts/fibroblasts with abundant lymphoplasmacytic infiltration and focal mucin deposition. The diagnosis was further supported by immunohistochemical findings, including positivity for cytokeratin, vimentin, SMA, and epithelial membrane antigen, although anaplastic lymphoma kinase (ALK) and STAT6 were negative.

Molecular studies have identified chromosomal 2p23 translocations in approximately 50% of IMT cases, leading to constitutive activation of ALK pathways.6 This genetic aberration correlates with tumour aggressiveness and local recurrence, supporting IMT’s classification as a true neoplasm rather than a reactive pseudotumour. Immunophenotypically, most IMTs express mesenchymal markers such as ALK (cytoplasmic/membranous), caldesmon, desmin, and SMA, with ALK reactivity aiding differentiation from histological mimics. Notably, our case showed an atypical immunoprofile with SMA positivity and ALK negativity, reflecting the phenotypic heterogeneity and the need for comprehensive molecular profiling in challenging cases.

Therapeutic strategies for IMT depend on disease stage and resectability. For localised lesions, complete surgical resection (R0 margins) achieves a 2% recurrence rate, whereas incomplete resection (R1/R2) increases recurrence risk to 60% (P<0.01).7 In our patient, thoracoscopic left upper lobectomy was performed with negative surgical margins, and no tumour recurrence was observed during the initial 3-month postoperative follow-up. Nonetheless, longer-term surveillance is recommended to confirm the absence of tumour recurrence. Non-resectable or recurrent cases require multimodal approaches, including radiotherapy (45-50 Gy), platinum-based chemotherapy, and ALK inhibitors for ALK-positive subtypes.

Emerging molecular insights have identified ALK rearrangements as key oncogenic drivers, positioning ALK-targeted therapies as both diagnostic and therapeutic tools.8 Clinical trials have demonstrated the efficacy of crizotinib: an initial phase 1 study (NCT01121588)9 achieved a 42.9% partial response rate in refractory paediatric/young adult IMTs (n=7), while cohort expansion (n=14) improved the overall response rate (ORR) to 86% (36% complete responses). Japanese studies corroborate these findings, with 100% ORR (1 complete response, 2 partial responses) in ALK-rearranged IMTs treated with crizotinib or alectinib.10 Nonetheless, therapeutic heterogeneity (ORR: 36%-100%), small sample sizes, and geographical bias necessitate standardised multicentre trials to validate efficacy and durability.

In summary, IMT represents a rare borderline neoplasm with intermediate malignant potential, distinct from the historically described IPT. The present case highlights the importance of accurate histopathological and immunohistochemical diagnosis, particularly in immunophenotypically atypical lesions, and underscores the need for long-term follow-up to monitor for potential recurrence.

Concept or design: X Mo.
Acquisition of data: Y Zhuang.
Analysis or interpretation of data: L Zhang.
Drafting of the manuscript: X Mo.
Critical revision of the manuscript for important intellectual content: C Chen.

All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This study was supported by the Science and Technology Development Project of Weifang (Ref No.: 2024YX077) and Weifang Youth Medical Talent Cultivation Support Program, China. The funders had no role in the study design, data collection/analysis/interpretation, or manuscript preparation.

This study was approved by the Ethics Committee of Weifang Second People’s Hospital, China (Ref No.: KY2024-077-01) and was conducted in accordance with the Declaration of Helsinki. The patient provided written informed consent for participation and publication of this case report, including the accompanying clinical images.

1. Höhne S, Milzsch M, Adams J, Kunze C, Finke R. Inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT): a representative literature review occasioned by a rare IMT of the transverse colon in a 9-year-old child. Tumori 2015;101:249-56. Crossref

2. Sagar AE, Jimenez CA, Shannon VR. Clinical and histopathologic correlates and management strategies for inflammatory myofibroblastic tumor of the lung. A case series and review of the literature. Med Oncol 2018;35:102. Crossref

3. Kiratli H, Uzun S, Varan A, Akyüz C, Orhan D. Management of anaplastic lymphoma kinase positive orbito-conjunctival inflammatory myofibroblastic tumor with crizotinib. J AAPOS 2016;20:260-3. Crossref

4. Surabhi VR, Chua S, Patel RP, Takahashi N, Lalwani N, Prasad SR. Inflammatory myofibroblastic tumors: current update. Radiol Clin North Am 2016;54:553-63. Crossref

5. Bedi D, Clark BZ, Carter GJ, et al. Prognostic significance of three-tiered World Health Organization classification of phyllodes tumor and correlation to Singapore General Hospital nomogram. Am J Clin Pathol 2022;158:362-71. Crossref

6. Pacheco E, Llorente JL, López-Hernández A, et al. Absence of chromosomal translocations and protein expression of ALK in sinonasal adenocarcinomas [in English, Spanish]. Acta Otorrinolaringol Esp 2017;68:9-14. Crossref

7. Baldi GG, Brahmi M, Lo Vullo S, et al. The activity of chemotherapy in inflammatory myofibroblastic tumors: a multicenter, European retrospective case series analysis. Oncologist 2020;25:e1777-84. Crossref

8. Mossé YP, Lim MS, Voss SD, et al. Safety and activity of crizotinib for paediatric patients with refractory solid tumours or anaplastic large-cell lymphoma: a Children’s Oncology Group phase 1 consortium study. Lancet Oncol 2013;14:472-80. Crossref

9. Antoniu SA. Crizotinib for EML4-ALK positive lung adenocarcinoma: a hope for the advanced disease? Evaluation of Kwak EL, Bang YJ, Camidge DR, et al. Anaplastic lymphoma kinase inhibition in non–small-cell lung cancer. N Engl J Med 2010;363(18):1693-703. Expert Opin Ther Targets 2011;15:351-3. Crossref

10. Takeyasu Y, Okuma HS, Kojima Y, et al. Impact of ALK inhibitors in patients with ALK-rearranged nonlung solid tumors. JCO Precis Oncol 2021;5:PO.20.00383. Crossref

A 67-year-old Asian female with no family history of heart disease was admitted to the Department of Psychosomatic Diseases at our hospital on 30 November 2024, primarily for intermittent anxiety and a 2-week history of general malaise but also headache, stomachache, backache, a sensation of choking and throat pain, dyspnoea, and, occasionally, a feeling of impending death. After attending a psychiatric hospital she was diagnosed with anxiety and prescribed oral flupentixol and melitracen tablets, zaleplon and oxazepam. Upon admission to the department, symptomatic interventions including anxiolytics and sleep aids were administered. On 3 December 2024 at 9:01 am, the patient abruptly encountered back pain. During the episode, the patient appeared to be choking but reported no perspiration or chest pain. Urgent electrocardiogram revealed ST segment elevation of 0.2 to 0.25 mV in the augmented vector right lead and depression of 0.2 to 0.35 mV in lead I, augmented vector left lead, lead II, and leads V1 to V5 (Fig 1). The high-sensitivity troponin was 0.061 ng/mL (normal, <0.016). In view of the suspected acute myocardial infarction, the patient was transferred to the Coronary Care Unit. Emergency coronary angiography revealed 90% stenosis in the proximal segment of the right coronary artery (RCA). The left anterior descending artery (LAD) and left circumflex artery were obscured in various angiographic views, while the blood flow in the distal segment of the RCA could be observed. Intravascular ultrasound examination of the RCA revealed a minimum lumen area of 2.59 mm² at the lesion site, with a plaque burden of 91%. Subsequent to balloon dilation, a single everolimus-eluting stent (PROMUS Element Plus; Boston Scientific, Marlborough [MA], United States) was implanted. Postoperatively there was no residual stenosis at the RCA lesion site, and distal blood flow was classified as TIMI III (the Thrombolysis in Myocardial Ischemia Trial III) [Fig 2a-d]. Postoperatively, the patient reported no pain in the precordial region or back.

Coronary computed tomography angiography (CTA) [Fig 2e and f] revealed that the left main trunk, LAD, and left circumflex artery did not arise from the left coronary sinus. The RCA originated from the right coronary sinus. These results aligned with the findings of coronary angiography. Echocardiography revealed that the left ventricular ejection fraction was 60% with mild mitral regurgitation and reduced left ventricular diastolic function. The patient’s condition improved after treatment and she was discharged home on 10 December. At 1-month follow-up, the patient reported no chest tightness, shortness of breath, or precordial pain, and electrocardiogram showed no signs of ischaemia.

A single coronary artery (SCA) is an uncommon coronary artery anomaly (CAA). The congenital absence of the left coronary artery (LCA) is an uncommon subtype of SCA, occurring with an incidence rate of 0.024%, with no discernible gender disparity.1 In 1979, Lipton classified SCA into types I, II, and III based on coronary origin, branching pattern, and disease course.2 In our patient, the single RCA was type R-I. As myocardial ischaemia is the aetiology of cardiovascular events induced by CAAs, coronary angiography is vital. Prior to percutaneous coronary intervention, a meticulous assessment of the surgical treatment strategy is essential.

The SCA form of CAA typically presents with no clinical symptoms and lacks specificity. Our patient exhibited cardiac-related symptoms, including backache, a sensation of choking, throat pain, and dyspnoea. Nonetheless the simultaneous occurrence of symptoms such as headache, stomachache and general malaise prompted a diagnosis of anxiety disorder. Coronary angiography was conducted to assess the extent of vascular stenosis but revealed the absence of an LCA, complicated by 90% stenosis in the proximal segment of the RCA. The lesion in the proximal segment of the patient’s RCA was comparable to that in the left main trunk. Thereafter, under intravascular ultrasound guidance, the coronary artery lesions were assessed, and a therapeutic approach was planned. Coronary CTA is crucial for identifying aberrant openings and congenital anomalies and unequivocally confirmed the congenital absence of the LAD in our patient. Secondary prevention of coronary heart disease is essential for these patients, ensuring proper maintenance of the lumen in the distal vessels of the RCA that supply the anterior and lateral walls.

The congenital absence of the LCA is an uncommon condition with an often non-specific clinical presentation. Clinically, if patients exhibit symptoms of angina pectoris or electrocardiogram alterations indicative of ischaemia, coronary CTA or coronary angiography should be promptly conducted to exclude congenital cardiovascular malformations. This enables clinicians to accurately diagnose and implement appropriate management.

All authors contributed to the concept or design of the study, acquisition of data, analysis or interpretation of data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

The study was funded by:
(1) Study of the Mechanism of Yangyin Shuxin Formula Inhibiting Calcium Overload in Cardiomyocytes through PI3K/IP3R Pathway, Improving Ejection Fraction, and Preserving Diastolic Function in Heart Failure, Key Research Project of Traditional Chinese Medicine in Tianjin (Ref No.: A0101); and
(2) Study on the immune-inflammatory mechanism of optimizing the polarization of macrophages mediated by IL-17 in Xinshengmaisan targeting myocardial fibrosis, Research Fund of the First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine (Ref No.: XB2024006).
The funders had no role in the study design, data collection/ analysis/interpretation, or manuscript preparation.

The study was approved by the Institutional Review Board of The First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, China (Ref No.: TYLL2024[Z]). Written informed consent was obtained from the patient for all treatments and procedures, and for the publication of this case report (including the accompanying clinical images).

1. Sampath A, Chandrasekaran K, Venugopal S, et al. Single coronary artery left (SCA L)–right coronary artery arising from mid-left anterior descending coronary artery: new variant of Lipton classification (SCA L-II) diagnosed by computed tomographic angiography. Echocardiography 2020;37:1642-5. Crossref

2. Lipton MJ, Barry WH, Obrez I, Silverman JF, Wexler L. Isolated single coronary artery: diagnosis, angiographic classification, and clinical significance. Radiology 1979;130:39-47. Crossref

A 30-year-old woman was diagnosed with systemic lupus erythematosus (SLE) in 2010 based on alopecia, facial rash, skin, biopsy-confirmed lupus nephritis, positive antinuclear antibodies and anti–double stranded DNA antibodies, and low complement levels. Over the past decade, her maximum exposure to prednisone was 40 mg/day with a minimum maintenance dose of 15 mg/day. She had been treated with multiple immunosuppressants including hydroxychloroquine, cyclophosphamide, mycophenolate mofetil, leflunomide, methotrexate, and azathioprine, due to persistent disease activity. Between 2020 and 2024, she was hospitalised multiple times for high fever, alopecia, facial rash, oral ulcers, vasculitis-like rash on the hands and scalp (online supplementary Fig 1a), and foamy urine (biopsy-confirmed lupus nephritis [class V and IV]) [online supplementary Fig 1b]. During each episode, macrophage activation syndrome (MAS) was identified using the HLH-2004 criteria based on elevated inflammatory indicators [C-reactive protein, interleukin 6 (IL-6), ferritin, C-X-C motif chemokine ligand 10 (CXCL10), chemokine (C-C motif) ligand 5 (CCL5), and interleukin-2 receptor], interferon genes (IFI44, MX1, and IRF1), and immune cell fluctuations (CD64 on neutrophils, CD4⁺ T cells, and CD8⁺ T cells). Dexamethasone and etoposide were administered during acute phases, and sequentially adjusted to cyclosporin A, mycophenolate mofetil, tacrolimus, tofacitinib, baricitinib, ruxolitinib, and telitacicept due to recurrent alopecia, rash, and joint pain. Despite these interventions, MAS relapsed, and prednisone could not be reduced below 30 mg/day.

In September 2023, 1 month after the last MAS episode, the patient again presented with MAS symptoms, including high fever (39°C), alopecia, vasculitis-like scalp rash, and oral ulcers (online supplementary Fig 1a). Laboratory tests revealed leukopenia (white blood cell count=1.25×10⁹/L), thrombocytopenia (platelet count=54×10⁹/L), anaemia (haemoglobin level=108 g/L), elevated C-reactive protein level (73.88 mg/L), erythrocyte sedimentation rate (78 mm/h), lactate dehydrogenase level (592 U/L), ferritin level (4508 ng/mL), splenomegaly, and no schistocytes. Extensive infectious workups, including blood cultures, next-generation sequencing, galactomannan, beta-D-glucan, T-SPOT, echocardiography, bone marrow biopsy, and high-resolution computed tomography, were negative, confirming a diagnosis of SLE-MAS. Given the recurrent nature of her condition, whole-exome sequencing was performed, identifying variants in GATA2 and MEFV of unclear significance (online supplementary Fig 2).

Multidimensional immune endotyping to evaluate disease conditions revealed: (1) abundant autoantibodies (online supplementary Fig 1c), high double-stranded DNA levels (>100 IU/mL detected by the Farr method) and low C3/C4 levels, indicating active SLE; (2) marked hyperinflammation with elevated levels of IL-6 (86.86 pg/mL), interferon gamma (IFN-γ) [42.18 pg/mL], C-reactive protein (99.99 mg/L), serum ferritin (6769 ng/mL), interleukin-2 receptor (1602 U/mL), CXCL10 (233.12 pg/mL) and CCL5 (27996.33 pg/mL); (3) upregulated interferon-stimulated genes (IFI44 176.59, MX1 328.63, and IRF1 84.32); and (4) immune dysregulation with increased neutrophil CD64 index, elevated CD8⁺ T cells, and decreased CD4⁺ T cells (Fig 1). Initial high-dose dexamethasone (10 mg every 12 hours) and cyclosporin A failed to control MAS with recurrence of fever and symptoms after 3 days. Given prior etoposide treatment and the risk of pancytopenia and infection, the treatment regimen was adjusted to include increased dexamethasone, tacrolimus, and intravenous immunoglobulin. Persistent inflammation led to the initiation of emapalumab (50 mg) on day 16 of hospital stay. Within 24 hours, fever subsided, and levels of C-reactive protein, IL-6, IFN-γ, CD64 on neutrophils, and interferon gene expression improved. Emapalumab was administered biweekly for four doses, significantly reducing steroid dependence and shortening the duration of hospitalisation. Three weeks later, the patient was discharged on oral prednisolone (60 mg/day) and tacrolimus (1 mg twice daily). One month later, tacrolimus was switched to baricitinib due to severe hair loss. At 9-month follow-up, inflammation and organ function normalised, enabling tapering of prednisone to 7.5 mg/day with baricitinib (Fig 2). The immune endotype changes, particularly CD8⁺ T-cell proliferation, were identified as a risk factor for MAS in this patient.

Emapalumab has been successfully administered in children with primary haemophagocytic lymphohistiocytosis and relapsed/refractory haemophagocytic lymphohistiocytosis.1 In our case, we jointly assessed the inflammatory state, interferon gene expression, and immune cell fluctuations to quickly identify this patient with SLE-MAS.

Patients with SLE and MAS have a high mortality rate,2 partly due to the difficulty in reaching an early MAS diagnosis since clinical features overlap with those of other conditions. Identifying immune endotypes may help detect MAS early. Interferon gamma plays a key role in SLE by activating neutrophils, CD8⁺ and CD4⁺ T cells, and macrophages, with its dysregulation contributing to MAS pathogenesis.3 In our patient, MAS presented as severe inflammation unresponsive to steroids or immunosuppressants but was effectively controlled by emapalumab. We observed elevated IFN-stimulated genes (IFI44, MX1, and IRF1) that normalised following emapalumab treatment.

Before treatment, the patient exhibited increased CXCL10 and CCL5 levels. Inflammatory markers were elevated, with cell analysis showing increased CD64⁺ neutrophils and CD8+ T cells, alongside reduced CD4⁺ T cells. In MAS, the percentage of CD8⁺ T cells outnumbers that of CD4⁺ T cells. Following emapalumab treatment, these abnormalities resolved, suggesting that excessive type II IFN signalling and CD8⁺ T cell overactivation drive SLE-MAS, potentially defining it as a distinct SLE subtype rather than a mere complication.

This case provides initial clinical evidence for the efficacy of emapalumab in refractory SLE-MAS although these findings are limited by the single-case nature and require validation in larger cohorts. The case highlights the importance of precise immune profiling in SLE-MAS and supports the use of emapalumab as a potential therapeutic strategy for refractory cases.

Concept or design: L Gu.
Acquisition of data: R Guo.
Analysis or interpretation of data: R Guo, S Ye.
Drafting of the manuscript: R Guo, L Gu.
Critical revision of the manuscript for important intellectual content: S Ye, L Gu.

All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This study was supported by Renji Hospital, School of Medicine, Shanghai Jiao Tong University, China (Grant Nos.: 2019NYLYCP0202 and RJTJ24-MS-020). The funder had no role in study design, data collection, analysis, interpretation, or manuscript preparation.

The study was approved by the Ethics Committee of Renji Hospital, School of Medicine, Shanghai Jiao Tong University, China (Ref No.: 2016-083). The patient was treated in accordance with the Declaration of Helsinki. Informed patient consent was obtained for publication of this case report, including the accompanying clinical images.

The supplementary material was provided by the authors and some information may not have been peer reviewed. Accepted supplementary material will be published as submitted by the authors, without any editing or formatting. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by the Hong Kong Academy of Medicine and the Hong Kong Medical Association. The Hong Kong Academy of Medicine and the Hong Kong Medical Association disclaim all liability and responsibility arising from any reliance placed on the content.

1. Locatelli F, Jordan MB, Allen C, et al. Emapalumab in children with primary hemophagocytic lymphohistiocytosis. N Engl J Med 2020;382:1811-22. Crossref

2. Borgia RE, Gerstein M, Levy DM, Silverman ED, Hiraki LT. Features, treatment, and outcomes of macrophage activation syndrome in childhood-onset systemic lupus erythematosus. Arthritis Rheumatol 2018;70:616-24. Crossref

3. Pollard KM, Cauvi DM, Toomey CB, Morris KV, Kono DH. Interferon-γ and systemic autoimmunity. Discov Med 2013;16:123-31.