To determine the gender-specific prevalence of pulmonary cysts typical for lymphangioleiomyomatosis (LAM) in adult patients with known tuberous sclerosis complex (TSC).A retrospective, cross-sectional study in a cohort of 206 adult TSC patients was performed. Institutional review board approval was obtained, and patient informed consent was waived. Patients had routinely undergone abdominal CT scanning between 1996 and 2006. All 186 patients (mean age 38 years; range 19-72 years; 91 (49 male patients) in whom at least the lung bases were depicted on computed tomography (CT) were included. Images were reviewed for the presence of pulmonary thin-walled cysts. Descriptive statistics, two sample t-test to compare means, and ?(2)-test to compare proportions were applied.CT demonstrated pulmonary thin-walled cysts in the lung bases in 52 (28 of 186 patients. Size varied from 2mm in diameter to more than 2cm. Pulmonary cysts were detected in 40 (42 of 95 female patients and in 12 (13 of 91 male patients (p<0.001). In general, cysts were larger and more numerous in women than in men. Only minimal cystic changes were found in four women and two men, moderate cystic changes were seen in three women and seven men, but considerable cystic changes were seen almost exclusively in women (33?women versus three men).CT demonstrated thin-walled pulmonary cysts in the lung bases in 28% of 186 included patients with tuberous sclerosis complex. Female patients were more affected than male patients.