Lymphangioleiomyomatosis screening in women with tuberous sclerosis.

BACKGROUND: Lymphangioleiomyomatosis (LAM) occurs in at least 40% of women with tuberous sclerosis complex (TSC), as diagnosed based on chest CT scan findings. Early identification may inform lifestyle choices and treatment decisions. Here we report LAM prevalence in a large TSC clinic and propose an approach to CT scan screening for LAM in women with TSC. METHODS: We retrospectively reviewed initial chest CT scans of all female patients with TSC aged ≥ 15 years seen at our center over a 12-year period. Each CT image slice was manually scored for the presence or absence of characteristic thin-walled cysts, and the diagnosis of LAM was made if the sum of the cysts on all slices exceeded three cysts. RESULTS: Of 133 female patients with TSC, 101 had chest CT scans available for review. Forty-eight (47.5%) met criteria for TSC-LAM on the initial CT scan. The risk of LAM was age dependent, rising by about 8% per year. The prevalence of LAM was 27% in subjects < 21 years of age and 81% in subjects > 40 years of age. Among asymptomatic subjects with LAM, 84% had cysts present in the single image at the level of the carina. Most subjects with LAM eventually developed pulmonary symptoms (63%), and 12.5% died from LAM. CONCLUSIONS: These results suggest that most women with TSC ultimately develop cystic changes consistent with LAM and that most cases can be identified from a single CT imaging slice at the level of the carina. TSC-LAM was associated with appreciable morbidity and mortality in this referral population. An age-based approach using limited CT scanning methods may facilitate screening and subsequent treatment decisions with decreased radiation exposure in this at-risk population.