Long-term survival in Ki-1 lymphoma.

Three patients with histologic and immunologic features of Ki-1-positive large cell lymphoma, who experienced long-term survival, are presented. These three patients at 2, 28, and 49 years of age had adenopathy; all cases had been initially misdiagnosed as metastatic carcinoma or malignant histiocytosis. On subsequent review, they had sinusal and diffuse growth of large pleomorphic cells that were Ber-H2 (Ki-1; CD 30) positive. One case marked as a T-cell lymphoma with UCHL1, one case expressed T-cell and B-cell markers, and one case was negative for both T-cell and B-cell markers. All patients received chemotherapy, and two received local radiation. One patient was not treated until 9 years after initial diagnosis. Two patients had several recurrences, but there has been no evidence of lymphoma in any of the three patients for 63 to 301 months; overall survival time has ranged from 14 to 25 years. These cases are the longest reported survivors with Ki-1 lymphoma; 5 years was the longest survival time previously reported. It also is noteworthy that Ber-H2 and other lymphoid-associated antigens appear to be preserved in formalin-fixed, paraffin-embedded tissues for prolonged periods. This may allow retrospective studies to evaluate the natural history of Ki-1 lymphomas, as well as their spontaneous or treatment-induced regression.