Clue to fine‐needle aspiration diagnosis of pleural pneumocystoma: Neovascularization and Langhans' giant cell reaction

Abstract

Pneumocystis pneumonia is a common component of the acquired immunodeficiency syndrome (AIDS) in the United States. Extrapulmonary pneumocystosis, however, is much less common. Rare cases have been reported in lymph nodes, bone marrow, spleen, pleura, gastrointestinal tract, liver, common bile duct, pancreas, skin, thyroid, and eye. A 39-yr-old man with history of chest wall injuries from gunshot and stabbing presented with multiple pleural masses clinically suspicious of metastatic deposits from an unknown primary. Fine-needle aspiration biopsy of the largest pleural mass revealed extrapulmonary pneumocystis, which led to the diagnosis of AIDS. Similar to the previous reports of pneumocystis mass lesions in extrapulmonary sites, the current case is associated with exuberant vascular proliferation and Langhans' giant cell reaction. Neovascularization and histiocytic influx from the newly formed blood vessels and Langhans' giant cell reaction seem to be a common tissue reaction to the massive deposition of pneumocystis organisms in extrapulmonary sites in patients with AIDS.