Malignant lymphoma obscured by concomitant extensive epithelioid granulomas: report of three cases with similar clinicopathologic features.

Three similar cases are described of an unusual combination of malignant lymphoma and extensive non-necrotic granulomas. The three patients presented with prominent splenomegaly without peripheral lymphadenopathy. They had normal or moderately elevated lymphocyte counts, abnormal lymphoid cells in the peripheral blood and bone marrow, and abnormalities of serum immunoglobulins. The lymphoid tumor was difficult to recognize but it was best identified in abdominal lymph nodes, it was composed of small atypical lymphocytes proliferating in a vaguely nodular pattern. The presence of multiple epithelioid granulomas obscured the neoplastic proliferation in the spleens and misled or delayed the final interpretation of the malignant disease. Abdominal lymph nodes and liver also contained granulomas although to a lesser extent. Studies of the lymphocyte surface characteristics in one patient suggested that the neoplasm derived from a monoclonal proliferation of B cells. The relationship between the exuberant epithelioid granulomas and the underlying neoplastic lymphoid proliferation is not clear. Regardless of whether it represents a distinct clinicopathological entity, recognition of this remarkable association has important practical implications since the lesions may be erroneously interpreted by the pathologist.