Lupus lymphadenitis: report of a case with immunohistologic studies on frozen sections.

A case of lupus lymphadenitis with frozen section immunohistologic studies is presented. Clinically, the patient had well-documented systemic lupus erythematosus (SLE) when rapid development of generalized lymphadenopathy raised the possibility of a diagnosis of malignant lymphoma. Histologically, the findings of paracortical foci of necrosis and hematoxylin bodies were diagnostic of SLE. Granulocytes were absent. Monoclonal antibodies applied to frozen sections demonstrated two predominant cell populations within and surrounding the paracortical zones of necrosis: OKM1+, Leu-M1+ histiocytes and OKT8+, Leu-4+ T cytotoxic/suppressor cells. In the lymph node not involved by necrosis, lymphoid follicles were composed of polytypic B cells and the interfollicular regions of T cells. Leu-3a+, Leu-4+ T helper/inducer cells outnumbered T cytotoxic/suppressor cells in a 3:1 ratio. Since lupus lymphadenitis may closely resemble histiocytic necrotizing lymphadenitis of Kikuchi and Fujimoto, particularly if hematoxylin bodies are not found, we compared the findings in this case with findings of cases of histiocytic necrotizing lymphadenitis of Kikuchi and Fujimoto reported in the literature. The immunologic findings in both diseases are similar. We conclude that immunologic studies using frozen sections are probably of no help in differentiating between these two disorders when histologic findings are not conclusive.