We report on three Chinese neonates with carnitine-acylcarnitine translocase deficiency. They presented within the first 48 hours of life. Two neonates were found in cardiac arrest; one of them survived after resuscitation. The third neonate suddenly developed cardiorespiratory insufficiency and succumbed eventually. The clustering of three cases in 5 years suggests that carnitine-acylcarnitine translocase deficiency is not rare in our Chinese population. We advocate that investigation for metabolic diseases including carnitine-acylcarnitine translocase deficiency should be performed in cases of sudden infant death and unexplained abrupt clinical deterioration in the early neonatal period. Non-ketotic hypoglycaemia is an early clue. The mainstay of initial treatment is glucose infusion at a rate greater than 7 mg/kg/minute, which inhibits beta-oxidation of fatty acids (the defective enzymatic steps in carnitine-acylcarnitine translocase deficiency) and thus prevents the accumulation of toxic long-chain acylcarnitines.

Poorly differentiated small cell carcinomas and malignant melanomas are among the rarest of primary colorectal malignancies. Although very aggressive and lethal, small cell carcinomas and the amelanotic variety of malignant melanomas have similar radiological features to adenocarcinomas. We present two different cases with these unusual tumours, with special emphasis on their dynamic contrast-enhanced magnetic resonance imaging features. The dynamic contrast-enhanced magnetic resonance imaging revealed that these tumours have a faster and stronger enhancement pattern than most adenocarcinomas. The technique is thus potentially useful for the preoperative diagnosis of unusual aggressive tumours and for guiding the choice of treatment.

Tuberculous involvement of the oesophagus is rare, and is usually caused by direct spread from adjacent afflicted structures. We report an 83-year-old male patient with oesophageal tuberculosis secondary to tuberculous mediastinal lymphadenitis who presented with non-specific symptoms of anorexia and lethargy. Upper gastro-intestinal endoscopy revealed an ulcerative tumour-like lesion in the mid-oesophagus suggesting oesophageal carcinoma. Repeated endoscopic biopsies revealed a non-specific acute-on-chronic inflammation consisting of non-caseating granulomas, with no evidence of malignancy. Endoscopic ultrasonography demonstrated that the oesophageal lesion was secondary to direct extension of mediastinal lymphadenopathy. The diagnosis of tuberculosis was eventually confirmed by histological and microbiological analysis of a surgically excised cervical lymph node. The patient responded promptly to treatment with antituberculous drugs. We suggest that oesophageal tuberculosis has to be kept in mind in the differential diagnosis of oesophageal ulcerohypertrophic lesions.

Metastatic Crohn's disease, in which non-caseating granulomatous infiltration of the skin occurs at sites separated from the gastro-intestinal tract by normal tissue, is the least common dermatologic manifestation of Crohn's disease. We report a 15-year-old girl with metastatic Crohn's disease presenting as granulomatous vulvar papules and nodules with typical histopathologic features. To the best of our knowledge, this is the first case of metastatic Crohn's disease in Chinese children reported in the English medical literature.

Subchondral insufficiency fracture of the femoral head is a recently recognised entity. There are a few cases reported in Japanese and Caucasian patients but none in the Hong Kong population. The condition typically occurs in elderly females with osteoporosis. Acute hip pain is the usual presentation. The patient may have concomitant insufficiency fractures elsewhere. Magnetic resonance imaging is usually required to make the diagnosis. The prognosis of the condition is unknown. Reported complications include rapid collapse of the femoral head and coxopathy. Joint replacement should be considered if conservative management fails.