Primary malignant lymphoma cutis.

Between 1934 and 1975, 16 patients with primary malignant lymphoma cutis were seen at the Ottawa clinic of the Ontario Cancer Foundation. The lesions were purplish, firm, dermal or hypodermal (or both) nodules, tumours and plaques. In all 16 the histopathologic diagnosis was diffuse non-Hodgkin's lymphoma; 12 were considered to have prognostically bad lymphomas. However, the prognosis of primary malignant lymphoma cutis is significantly more favourable than is implied by the stage IV designation that such localized extranodal involvement would have required under the Rye clinical staging classification.