Cutaneous B-cell lymphoma with signet ring-cell morphology - A clinicopathologic and immunohistochemical study of three cases

Three cases of primary cutaneous B-cell lymphoma with prominent signet ring -cell features are presented. The patients were three men between the ages of 37 years and 74 years (average, 55.5 years). Clinically, the three patie nts presented with multiple skin nodules. In one patient. the nodules had b een present for approximately 5 weeks, although in the two other patients, the nodules were of unknown duration. The lesions were located in the upper extremities (forearm) and measured from 2 cm to 3 cm in diameter. No evide nce of lymphadenopathy was observed in any of the patients. Surgical excisi on of the nodules was performed. Histologically, in two cases, the superfic ial and deep dermis was replaced by a diffuse cellular proliferation, and i n one patient, the tumor cell population adopted a nodular pattern of growt h involving adnexal structures and infiltrating the subcutaneous fat. In al l cases, the tumors were composed of cells showing signet ring-cell feature s, with striking indentation of the nuclei toward the periphery of the cell . Immunohistochemical studies using antibodies for B-cell and T-cell marker s (L-26 and UCHL) as well as antibodies for leukocyte common antigen, kerat in, and kappa and lambda light chains were performed in all cases. The turn er cells showed a positive reaction for leukocyte common antigen, L-26, and lambda light chain restriction. Follow-up information was only available i n one patient, who has remained alive and well 2 years after diagnosis with out evidence of progression of the disease. The present cases highlight the importance of recognizing this unusual morphologic type of lymphoma so as to arrive at a correct diagnosis.