Perirenal mass of Langerhans cell histiocytosis.

A 15-month-old girl with Langerhans cell histiocytosis (LCH), Letterer-Siwe disease, was referred to our hospital in 1984. Whilst on treatment with cytotoxic drugs, a perirenal mass was detected and hydronephrosis became evident when she was 29 months old. Percutaneous nephrostomy tubes were placed in the pelvis, bilaterally and replaced every 6 months. The mass was not completely controlled and chronic pyelonephritis continued. Biopsy of the mass convoluted kidney hilus revealed histiocytic invasion. Although multiple organ systems are involved in LCH and abdominal malignant tumours may be accompanied by hydronephrosis, to our knowledge, this is the first case report of abdominal LCH and the ensuing hydronephrosis. Percutaneous nephrostomy tubes proved useful, but more convenient, less painful and infection-limited approaches need to be designed.