A rare case of pyothorax-associated large B-cell lymphoma occurring in Hong Kong is reported. The patient was a 64-year-old Chinese male who presented with shortness of breath and pleuritic pain. Radiological examination revealed left pleural thickening associated with bilateral pleural effusion. Open biopsy of the thickened parietal pleura revealed occasional large malignant lymphoid cells of B lineage admixed with fibrin and hyalinised fibrous tissue. These lymphoma cells were shown to harbour both Epstein-Barr virus and human herpesvirus type 8 by in situ hybridisation and immunohistochemical study, respectively. There was no associated lymphadenopathy and hepatosplenomegaly. The clinicoradiological presentation and pathological findings thus fulfilled the criteria of the so-called pyothorax-associated large B-cell lymphoma. Awareness of this rare entity, together with diligent histological examination and proper application of ancillary investigative techniques, are essential for making a correct diagnosis. The co-infection with Epstein-Barr virus and human herpesvirus type 8 in this case also suggests a possible pathogenetic relationship between pyothorax-associated large B-cell lymphoma and primary effusion lymphoma.

A 50-year-old Chinese woman with a chronic 20-year history of ataxic gait associated with dry eyes and mouth, was admitted to hospital after a single episode of syncope. Magnetic resonance imaging scans showed a large left frontal hypodense lesion suggestive of a glioma. Craniotomy was performed and the lesion excised, with histology showing only infarcted tissue and no malignant cells. Further diagnostic evaluation revealed that the patient had primary Sjogren’s syndrome, with demyelinating polyneuropathy. In the absence of risk factors for stroke, it was considered likely that the cerebral infarct was secondary to autoimmune-related vasculitis. Functional neuroimaging, such as magnetic resonance spectroscopy, should be considered in evaluating doubtful or unusual brain lesions in patients with autoimmune disease.

We report the case of a 71-year-old Japanese woman with mixed connective tissue disease and increased levels of platelet-associated immunoglobulin G. After administration of oral prednisolone, platelet-associated immunoglobulin G levels decreased with a simultaneous increase in the number of platelets, suggesting that the thrombocytopenia observed in this patient was mediated by immune mechanisms. This is the first reported case of increased platelet-associated immunoglobulin G levels in a patient with mixed connective tissue disease.

Five cases of paediatric stroke are reported. Two patients presented with idiopathic stroke, another following vertebral artery dissection, one second-ary to Moyamoya disease, and one patient with the syndrome of mitochon-drial encephalopathy, lactic acidosis, and stroke-like episodes. The presentation, investigation, and management of paediatric stroke are discussed.

We report the case of a newborn baby with carbamoyl phosphate synthetase deficiency. He presented at 2 weeks of life, deteriorating to a state of hyperammonaemic coma and respiratory failure. Rapid detoxification was successfully achieved by continuous venovenous haemofiltration while a definitive diagnosis and treatment were determined. The ammonia clearance achieved by continuous venovenous haemofiltration was greater than 20 mL/min/m2 , which is superior to that achieved by peritoneal dialysis and arteriovenous haemofiltration in this age-group.