Renal smooth muscle tumor with features of lymphangioleiomyomatosis. Problems in histological diagnosis

A 44-year-old woman with left kidney tumor involving the perirenal and retroperitoneal lymph nodes is presented. Imaging findings including ultrasonography and computerized tomography showed renal and para-aortic masses and no features of lymphangioleiomyomatosis or angiomyolipoma were seen. The histopathological examination was considered as a renal smooth muscle tumor with features of lymphangioleiomyomatosis. Diagnosis considerations, particularly histopathological, immunohistochemical and hormonal studies are discussed and we comment the distinction of this case from the benign mesenchymal tumors.