Pulmonary function tests for lymphangioleiomyomatosis screening in women with tuberous sclerosis complex

Abstract

The advent of therapies for lymphangioleiomyiomatosis (LAM) has made early diagnosis important in women with tuberous sclerosis complex (TSC), although the lifelong cumulative radiation exposure caused by CT imaging screening should not be underestimated. In 200 TSC outpatients of San Paolo Hospital (Milan, Italy) we retrospectively investigated 1) the role of pulmonary function tests (PFTs) for screening purpose, 2) the association between LAM and other manifestations of TSC (e.g. demography, extrapulmonary manifestations, genetic mutations, etc.), and 3) the features of patients with multifocal micronodular pneumocyte hyperplasia (MMPH). Eighty-six adult women underwent computed tomography for LAM diagnosis; pulmonary involvement was found in 66 patients (77%, 49% LAM with or without MMPH, and 28% MMPH alone). LAM patients were older, with a higher rate of pneumothorax, presented more frequently renal and hepatic angiomyolipomas, and tended to have a TSC2 mutation profile. PFTs, assessed in 64% of women unaffected by cognitive impairments, revealed a lower lung diffusion capacity in LAM patients. In multivariate analysis age, but not PFTs, resulted independently associated with LAM diagnosis. Patients with MMPH alone did not show specific clinical, functional of genetic features. A mild respiratory impairment was most common in LAM-TSC patients; PFTs, even if indicated to assess pulmonary function impairment, are feasible in a limited number of patients, and are not significantly useful as a screening tool in women with TSC.