Rebound hyperplasia of the thymus with secondary intrathymic bleeding. Rare differential diagnosis of acute chest pain

HISTORY AND ADMISSION FINDINGS: A 41-year-old man was admitted, in reduced general condition, having for several hours experienced acute left chest pain and dyspnoea. On examination there was dullness on percussion over the base of the left lung with decreased breath sounds. At the age of 28 years he had been placed on peritoneal dialysis for renal failure due to congenital kidney aplasia. A year later he had been given a renal transplant, which had to be removed a year before admission because of transplant glomerulopathy. He had been on peritoneal dialysis since then. INVESTIGATIONS: Haemoglobin concentration, erythrocyte count and haematocrit gradually fell. A chest X-ray revealed a mediastinum widened to the left. Computed tomography demonstrated a blood-containing mediastinal tumour and a haemothorax. DIAGNOSIS, TREATMENT AND COURSE: A haemorrhagic mediastinal tumour was excised at thoracotomy. Histology of the specimen showed thymus hyperplasia with extensive fresh bleeding in the thymus. The postoperative course was without complication and the patient's exercise capacity returned to normal. CONCLUSION: Thymus hyperplasia with life-threatening spontaneous haemorrhage can occur after termination of immunosuppression following transplant removal.