Pulmonary lymphangiomatosis: insights into an ultra-rare disease

Pulmonary lymphangiomatosis (PL) is an ultrarare disease characterized by diffuse infiltration of the lung, pleura and/or mediastinum by abnormal lymphatic proliferation. Consented diagnostic or treatment approaches are not established. We therefore aimed to collect data on diagnostics and treatments in a cohort of patients with PL from a tertiary center for rare lung diseases.

Clinical, radiological and outcome data from PL patients were collected retrospectively.

12 patients were diagnosed between 1996 and 2022 in our center. PL was diagnosed more commonly in female (58%), never smokers (75%) and younger patients (mean age 42 years). Main clinical symptoms comprised haem- and chyloptysis (58%) and dyspnea on exertion (83%). Pulmonary function was mostly restrictive (mean VC 59%) with impaired DLCO (mean 65%). Radiological assessment mainly showed mediastinal involvement (83%), and pleural effusion (67%), pleural thickening (67%) and bronchial wall thickening (67%) while interstitial changes were rare. Diagnosis was confirmed by surgical or transbronchial cryobiopsy. 8 patients were treated with sirolimus, 3 of these combined with a surgical intervention and in one case surgical intervention was necessary 9 months after initiation of sirolimus. Clinical and radiological improvement was demonstrated for all patients treated with sirolimus. 1 patient received a lung transplant due disease progression. Survival rates were 90% after a mean follow up of at least 3 months.

This case series illustrates the variability of the clinical presentation of PL. Among our patients, those treated with sirolimus showed significant clinical, functional and radiological improvement. However, further investigation is needed to understand the pathogenesis of lymphangiomatosis in order to establish therapeutic approaches.