Primary extranodal non-Hodgkin's lymphoma of the oral region.

Seventy cases (47M, 23F) of primary extranodal non-Hodgkin's lymphoma of the oral region were studied to determine tumor characteristics. The most frequent disease sites were the palate (21 cases), gingiva (17 cases) and parotid gland (13 cases). Each lymphoma was classified according to the criteria of the Working Formulation for Clinical Usage. Only 5.7% of cases were follicular lymphomas while diffuse lymphomas had a high incidence. Histologic subtypes included small lymphocytic (1%), small cleaved cell (7%), mixed small and large cell (20%), large cell (43%), large cell, immunoblastic (17%), lymphoblastic (9%) and small non-cleaved cell lymphoma (3%). Immunologic study utilizing the avidin-biotinylated horseradish peroxidase complex (ABC) technique demonstrated the presence of intracytoplasmic monoclonal immunoglobulin in 24 (34%) of the suggested B-cell lymphoma cases; 20 tumors (28%) were classified as T-cell lymphoma based on a positive reaction for mouse monoclonal antibody (UCHL-1) to T-cell related membrane antigen; 11 tumors (16%) contained intracytoplasmic alpha 1-antitrypsin, suggesting true histiocytic lymphoma; 15 tumors (22%) did not contain immunoglobulin, UCHL-1 or alpha 1-antitrypsin positive cells and showed no definite characteristics.