The clinicopathologic features of 114 Japanese patients with extranodal non-Hodgkin's lymphoma of the head and neck region were analyzed. The median age was 60.5 years and the ma1e:female ratio was 1.5:l. The most common site of involvement was Waldeyer's ring, followed by the oral cavity, thyroid gland, paranasal sinuses, nasal cavity, and larynx. Seventy-five percent of the patients were in Stage I or Stage I1 at admission. Histologically, diffuse lymphoma accounted for 94% and follicular lymphoma for 6% of cases. The histologic grade according to the Working Formulation System of the National Cancer Institute was low in 11%, intermediate in and high in 14% of cases. Immunohistochemical study showed that the majority of the cases were of B-cell type and only 13 cases (11%) were of the T-cell type. Peripheral T-cell lymphomas (eight cases) mainly occurred in the nasopharynx and nasal cavity, whereas four of five thymic T-cell lymphomas were found in the palatine tonsil. The over-all !&year survival rate was 54%, and the factors affecting survival were sex, histologic grade, T/B phenotype, clinical stage, and the site of initial presentation. Five-year survival with nasal cavity and Waldeyer's ring lymphoma was 24% and 46%, respectively. The poor prognosis of lymphomas at these sites might result from the predominance of T-cell lymphoma, the paucity of low grade lymphoma, and the relatively high incidence of cases that were in an advanced stage at presentation. In Stage 11, patients treated with combined therapy tended to have a better 5-year survival rate than those treated with radiotherapy alone. Cancer 66: 1190-1197,1990. HE HEAD AND NECK REGION is One of the most COm-T mon sites of extranodal non-Hodgkin's lymphoma, and there have been several previous reports on this subject.'-' The most common site of involvement is Waldeyer's and more than half the patients are in an early stage at p r e s e n t a t i ~n . ~, ~. ~, ~ Diffuse lymphoma is pre-From the Departments of *Pathology, $Radiology, and 11 Surgery,