Successful treatment of a patient with chyluria due to lymphangioleiomyomatosis using sirolimus

Abstract Lymphangioleiomyomatosis (LAM) is a rare and progressive neoplastic disease of young woman, characterized by the proliferation of abnormal smooth muscle-like cells (LAM cells) in the lungs and axial lymphatics. A 44-year-old woman was referred to our hospital because pleural effusion was detected during a health checkup. She had chylothorax, chylous ascites, and chyluria, and her computed tomography scan showed a solid tumor in the pelvis. Surgical biopsy was performed; she was diagnosed as having LAM. We could not control the fluid collection and chyluria using standard medical treatments. Therefore, we chose to administer sirolimus, and her symptoms dramatically improved. The mechanism of chyluria presumably involved LAM cell infiltrates in the ureter via the lymphatic vessel flow, which causes LAM to develop because of ureter wall exposure.