Primary lymphoma of bone: a clinicopathologic study of 25 cases reported over 10 years. Twenty-five cases of primary lymphoma of bone (PLB) reported over a 10-year period were reviewed. The presenting symptom was related to involvement of a single bone with or without regional nodal disease. None showed dissemination of lymphoma in the subsequent six months. Patients affected were 7-65 years of age. An equal predilection for the axial and appendicular skeleton was noted. Histologically, the commonest subtype was diffuse histiocytic lymphoma (DHL, 17 cases), whereas four were poorly differentiated lymphocytic (PDL) type and another four were unclassifiable. Follow-up was available in 18 out of 25 patients for periods ranging from 7 months to 8 years. On clinicopathologic correlation we found that 75% of disease-free patients had a DHL whereas 60% of those alive with disease had a PDL. This study reiterates the view that PLB has a good prognosis and the DHL subtype is especially amenable to complete eradication. 