Extrapulmonary pneumocystosis: the first 50 cases.

Over the last 35 years, 50 cases of extrapulmonary infection with Pneumocystis carinii have been reported in the literature throughout the world. Use of prophylactic aerosolized pentamidine may have facilitated the relative prevalence of extrapulmonary disease because of its inadequate systemic distribution. An increase in reported cases of infections due to P. carinii has been seen in conjunction with AIDS, but extrapulmonary pneumocystosis represents less than 1% of all cases of infection with P. carinii. Several organs or tissues may be involved, but the most common sites are lymph nodes, spleen, liver, and bone marrow. Extrapulmonary spread of P. carinii infection occurs via both lymphatic and hematogenous routes. While all patients with disseminated forms of this infection die rapidly, survival for patients with AIDS is possible if systemic treatment is provided, if a single extrapulmonary site is involved, and if no concomitant pneumonia is present. Because of the increasing frequency of this condition in patients who do not have pneumonia due to P. carinii, extrapulmonary pneumocystosis should be included among the AIDS-defining criteria.