Lymphomas presenting as histologically unclassified neoplasms: characteristics and response to treatment.

Malignant lymphoma is frequently diagnosed when immunohistochemical techniques are applied to otherwise unclassified neoplasms. In this analysis of 35 patients with a histologically unclassified neoplasm that expressed leukocyte-common antigen(s) (LCA), actuarial survival was 63%, and 45% of patients were free from disease progression at 30 months following treatment as for lymphoma. The clinical features at diagnosis and the results of combination chemotherapy were found to be similar to a group of patients with a diagnosis of diffuse large-cell lymphoma (DLCL) concurrently treated at this institution. This study further emphasizes the importance of improved diagnostic techniques in the management of histologically unclassified tumors.