Transformed malignant lymphoma from Lennert's lesion is a CD4+ T cell lymphoma: an immunohistochemical study.

We describe a case of Lennert's lesion terminating in T cell non-Hodgkin's lymphoma (NHL). A 53-year-old woman showed inguinal lymphadenopathy. This was histologically interpreted as toxoplasmic lymphadenitis. However, Lennert's lesion was diagnosed in subsequent biopsies. Because additional lymphadenopathy and constitutional symptoms were absent, anti-neoplastic therapy was not given. During the five and a half years after the initial biopsy, generalized lymphadenopathy and constitutional symptoms developed. Histological examination of the cervical lymph node disclosed NHL, diffuse, large cell type. Transformed lymphoma cells were confirmed to be of peripheral T cell origin with a helper/inducer phenotype. We speculate that some cases of Lennert's lesion have a potentiality of spontaneous transformation into high grade malignant lymphoma associated with disappearance of epithelioid histiocytes.