Malignant histiocytosis after lymphoblastic lymphoma.

Malignant histiocytosis developed in a 19-year-old boy 3 1/2 years after the initial diagnosis of lymphoblastic lymphoma of T-cell origin. The experience with this young adult suggests that a close surveillance of the survivors of lymphoma is mandatory, and a prompt biopsy of enlarged lymph nodes in patients treated for lymphoma should be a routine procedure.