Malignant lymphoma arising in a large congenital neurofibroma of the head and neck. Report of a case.

A lymphoma developed in a large neurofibroma in a young woman who had no other stigmata of neurofibromatosis. The neurofibroma was congenital and extensively involved the soft tissue and bone of the face and neck. Despite multiple attempts to excise the neurofibroma, it persistently recurred. At the age of 30 the patient underwent another resection of the lesion, and a follicular, mixed, small and large cell lymphoma was present within the neurofibroma. Over 3 years the lymphoma transformed into a diffuse large cell type despite the fact that it remained localized to the neurofibroma. After the lymphoma had transformed, the patient received multiagent chemotherapy. She responded well, and a repeat biopsy showed no residual lymphoma. She is alive and well 25 months after completion of chemotherapy. To the best of our knowledge, this is the first report of a lymphoma arising in a soft tissue neoplasm.