Reticulum cell sarcomas (large cell lymphomas) presenting in the skin. High frequency of true histiocytic lymphoma.

The clinical and histologic data from 12 patients with "reticulum cell sarcoma" (large cell lymphoma) presenting in the skin were reviewed. Moreover, when appropriate material was available additional immunological, cytochemical and ultrastructural techniques were used to define the nature of the neoplastic cells. Eight tumors were found to be of true histiocytic origin (histiocytic sarcoma), three of B-cell origin (two B-immunoblastic lymphomas and one centroblastic or large noncleaved follicle center cell lymphoma) and one case could not be classified. Possible explanations for the discrepancy between the current report and other studies as to the frequency of true histiocytic tumors will be discussed. The differentiation into T-cell, B-cell and true histiocytic lymphomas appears to be important, not only because of different clinical behaviour, but possibly also from a therapeutical point of view.