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.