The aim of the present study was to report clinical, radiological and bronchoalveolar lavage (BAL) findings in patients with pulmonary manifestations of HIV-associated multicentric Castleman's disease (MCD). This was a retrospective study of 12 patients with histologically proven MCD. Clinical manifestations were as follows: dyspnoea (nine out of 12 cases), cough (n = 10), bilateral crackles (n = 10), together with high fever, malaise, peripheral lymphadenopathy (n = 12), and hepatosplenomegaly (n = 10). Two patients developed acute respiratory distress syndrome. Chest radiographs and computed tomography scans showed reticular (n = 7) and/or nodular (n = 7) interstitial patterns, with mediastinal lymphadenopathy (n = 9), and bilateral pleural effusion (n = 3). Fibreoptic endoscopy was normal in all cases. BAL analysis showed hypercellularity (n = 6) and/or lymphocytosis (n = 6), and human herpesvirus-8 DNA was detected in two out of two cases. Specific stains and cultures for pathogens were negative. All patients received etoposide and/or vinblastine, and improved after 2-4 days. Relapses were frequent (50 attacks in 12 patients). Six patients developed a non-Hodgkin's lymphoma, and five died. In conclusion, the pulmonary manifestation of HIV-related multicentric Castleman's disease is an acute reticulo-nodular interstitial pneumonitis, associated with severe systemic symptoms and peripheral lymphadenopathy. In bronchoalveolar lavage fluid, cellularity is not specific and human herpesvirus-8 DNA is detected. The clinical course is specific due to a rapid onset and regression, frequent relapses and a high occurrence of non-Hodgkin's lymphoma.