Development of Ki-1 lymphoma in a child suffering from multicentric reticulohistiocytosis.

We report a case of Ki-1 lymphoma that developed in a 16-year-old youth who had suffered from multicentric reticulohistiocytosis for 10 years. Over the past 3 years he had had a peculiar sclerosing lesion of the leg for which oral prednisone 5 mg daily was tried for one year, with a moderate effect. He developed a marked swelling of the inguinal lymphadenopathy on the same side as the affected leg lesion, which also developed a prominent swelling of the skin surrounding the sclerosed area. Immunohistochemical analysis of the lymph node biopsy revealed the features of Ki-1 lymphoma. This is the first case of association of multicentric reticulohistiocytosis with Ki-1 lymphoma.