VEGFD and lymphangioleiomyomatosis: In cases of diagnostic uncertainty, the measurement of VEGF-D is particularly useful-in the context of investigation of the etiology of diffuse cystic lung disease in various populations, including that of Brazil, a serum VEGF-D level above 800 pg/mL has a specificity of nearly 100% for the diagnosis of LAM, with the potential to preclude the need for lung biopsy in patients without other clinical manifestations.