Diagnostic pathology in the acquired immunodeficiency syndrome. Surgical pathology and cytology experience with 67 patients.

We report the pathologic findings in specimens submitted for histologic and cytologic evaluation from 67 patients with the acquired immunodeficiency syndrome. A wide variety of opportunistic pathogens were identified in 41 patients. Mycobacterium avium-intracellulare evoked only a mild host response: granulomas, if present, were poorly formed. Biopsy specimens showing cytomegalovirus gastroenteritis required sections at multiple levels to demonstrate inclusions. Combined histologic and cytologic evaluation can increase the diagnostic yield in pulmonary and esophageal infections. Kaposi's sarcoma was found in biopsy specimens from 29 patients. Early lesions were often extremely subtle, yet distinct from, benign vascular proliferations in involuted lymph nodes. Malignant lymphoma was diagnosed in ten homosexual men who were suspected of having the acquired immunodeficiency syndrome. The lymphomas were characterized by B-cell origin, a diffuse pattern, frequent extranodal presentations, and an aggressive clinical course with prominent central nervous system involvement.