VEGFD and lymphangiomyoma: ,28 In the algorithm suggested in the guidelines of the American Thoracic Society and the Japanese Respiratory Society, the second step in the diagnostic workup of LAM, after clinical evaluation, is HRCT, and the identification of the classic CT pattern defines the diagnosis if associated with other findings, such as angiomyolipomas and lymphangioleiomyomas, the presence of TSC or elevated serum levels of VEGF-D.28