Retroperitoneal lymphangioleiomyoma with lymph node involvement: A pathologic-radiologic correlation of a rare form of myomelanocytic tumor.

Lymphangioleiomyomatosis (LAM) is a rare and slowly progressive disorder that usually arises in the lung, affects exclusively women in their childbearing years, and typically presents with progressive dyspnea on exertion and pneumothorax. Infrequently, extra-pulmonary LAM can occur in the retroperitoneum, uterine wall, mediastinum and intraperitoneal lymph nodes. Histologically, LAM is characterized by a proliferation of perivascular epithelioid cells (PEC) that express markers for both melanocytes and smooth muscle cells. We report a case of a peripancreatic retroperitoneal mass that was incidentally discovered on magnetic resonance image (MRI) scan of a 38-year-old female. The morphologic findings and the immunohistochemical staining were consistent with a lymphangioleiomyoma. The radiologic and pathologic correlation along with differential diagnosis of this rare entity is discussed.

Primary aortic myxofibrosarcoma mimicking thrombus: findings on CT, MRI, and angiography.

Aortic sarcoma is a rare vascular malignancy. We report a case of primary aortic myxofibrosarcoma mimicking thrombus. This neoplasm demonstrated no contrast enhancement on computed tomography or magnetic resonance imaging and was clinically suspected to represent a large thrombus, although aortic primary neoplasm was considered in the differential diagnosis on the basis of imaging. Biopsies of the aortic lesion and a concurrent brain lesion were consistent with the diagnosis of aortic myxofibrosarcoma with brain metastasis. This report highlights overlapping imaging features between primary aortic sarcoma and vascular thrombus and the importance of considering neoplastic conditions in the differential diagnosis of large intravascular soft tissue lesions.