Kaposi's sarcoma presenting as pulmonary disease in the acquired immunodeficiency syndrome: diagnosis by lung biopsy.

Kaposi's sarcoma frequently develops in patients with the acquired immunodeficiency syndrome (AIDS), and in most cases cutaneous lesions herald the disease. Although the lungs are often involved when the neoplasm becomes disseminated, it is rare for the initial diagnosis to be made by lung biopsy. This report describes two patients with AIDS in whom Kaposi's sarcoma was present in lung biopsy specimens and in whom there was no other systemic evidence of the neoplasm. Both patients experienced hemoptysis, and pulmonary hemorrhage accompanied the neoplasm in each case. Only five microscopic foci of tumor were found in a total of 44 sections of lung examined. The focal distribution of the lesions in the pulmonary interstitium and the presence of coexisting lung disease posed problems in the evaluation of the biopsies. Awareness of the appearances of Kaposi's sarcoma in lung tissue is important because the neoplasm will probably be encountered in lung biopsies with increasing frequency as more cases of AIDS are discovered.