Primary anorectal lymphoma. A new manifestation of the acquired immune deficiency syndrome (AIDS).

Non-Hodgkin's lymphomas with particular clinicopathologic features occur with a high incidence in homosexual men affected by AIDS. More frequently than in the general population, these lymphomas have an extranodal location including the gastrointestinal tract. We have recently observed four cases of AIDS-associated lymphomas whose primary location is in the lower rectum and anus. The patients were 27 to 44 years of age, had greatly depressed helper-suppressor T-cell ratios, and antibodies to human immunodeficiency virus (HIV). All four presented with anorectal symptoms and originally had surgery for anorectal fistulas or tumor masses. When staged, three patients had no other organ involvement, the fourth only had lymphoma in an axillary lymph node, and all four had large tumor masses confined within the rectum. In terms of histology, the lymphomas were of undifferentiated or of large cell type and of B-cell phenotype. Lymphomas with primary or major location in the rectum are a rare occurrence in the general population, and until recently, are rare even among the lymphomas associated with the immune deficiency syndrome. At the Lenox Hill Hospital in New York City, no rectal lymphoma among the 58 cases of AIDS-related lymphoma diagnosed during the past 4 years was recorded until 10 months ago. The recognition of the new feature in presentation, a neoplasm associated with AIDS, is obviously important for its early diagnosis and treatment. Its unusual occurrence at the suspected portal of entry of the HIV infection is of interest because it may provide new clues to the association between AIDS and neoplasia.