Lymphoepithelioid cellular lymphoma (Lennert's lymphoma) in association with malignant lymphoma, histiocytic type.

The present case is unusual in that it demonstrates the presence of the histologic pattern of Lennert's lymphoma in a patient who had a 14-year history of recurrent reticulum cell sarcoma (histiocytic lymphoma). This particular lesion also exhibits clinical and pathologic similarities to angioimmunoblastic lymphadenopathy and malignant lymphoma of peripheral T-lymphocyte origin. Whether the appearance of Lennert's lymphoma in this patient represents a regression of the previous reticulum cell sarcoma (histiocytic lymphoma) to a more benign form, a response to therapy, an alteration in the immune system, or a new lymphoreticular malignancy remains to be answered.