Lymphoepitheloid cell malignant lymphoma (Lennert).

Typical epitheloid cell formations were found in 175 of 500 cases of various types of Hodgkin's disease. No distinctive behaviour was found in cases with epitheloid structures. Close attention has been devoted to a further series of 23 lymphoepitheloid cell malignant lymphomata marked by focal nuclear atypicality in their epitheloid cell granulomas, which destroyed the basic neoplastic structure of the lymph node in many cases, necessitating further biopsy. In this series not only Hodgkin's disease (7 cases) but also some malignant lymphomas of non Hodgkin's types (3 x immunoblastoma, 3 x immunocytoma and 2 x T-lymphoblastoma) were found. In 6 cases only a tentative diagnosis of lymphoepitheloid cell malignant lymphoma could be made. The epitheloid granulomatous reaction tended to disappear gradually in all cases by repeated check-ups, and was apparently a secondary phenomenon. The cause of the epitheloid cell atypia was not evident although it proved to be an important diagnostic feature identifying an independent form of lymphoepitheloid malignant lymphoma. The subsequent development of this lesion suggested a mildly pleiomorphic highly malignant lymphoma, which might be of B cell origin, but sometimes demonstrably of the T cell series.