Acquired immunodeficiency syndrome. Distinctive features of bone marrow biopsies.

Bone marrow biopsies from 30 patients with acquired immunodeficiency syndrome (AIDS), diagnosed according to accepted clinical criteria, were studied in order to determine if characteristic histopathologic features were present. The biopsies were compared with 20 biopsy specimens submitted from patients with fever of unknown origin or with known neoplastic disease, including four biopsies from patients with a history of narcotics addiction being treated in the methadone clinic, and with biopsies from three homosexual men who did not have AIDS. Characteristic biopsy features were recognized in 31 (86%) of 36 biopsy specimens from AIDS patients. Nineteen of 36 patients (53%) showed a distinctive pattern of hypercellularity in which hematic cells (immature granulocytic cells, megakaryocytes, eosinophils, and large lymphocytes) separated, but did not efface, fat cells; these cells were designated as "AIDS-pattern." Twelve specimens showed a less complete (probable-AIDS) bone marrow change. Reticulin fibers were increased in 28 of 36 biopsies.