A Case of Mediastinal Angiomyolipoma

Abstract

Angiomyolipoma is a common tumor of the kidney but has rarely been found in the mediastinum. We report a case of angiomyolipoma of the posterior mediastinum in a 62-year-old woman. She experienced exertional dyspnea and intermittent cough at admission. Computed tomography indicated a tumor located at the left paravertebral and upper posterior mediastinum and MRI imaging demonstrated a mass with low signal intensity in T1-weighted image at T4-5 level. Thoracotomy was done for surgical removal of the tumor and histologic examination revealed a mesenchymal tumor composed of mature fat, capillaries and smooth muscle fibers. The tumor was immunohistochemically positive for CD34 and factor-VIII (for vascular component) smooth muscle actin (for smooth muscle component) and S-100 protein (for fat component). There have been four case reports about mediastinal angiomyolipoma, namely three Japanese cases and one French case. It is suggested that angiomyolipoma could be considered for the differential diagnosis of mediastinal tumors.

Successful thoracoscopic resection of a large mediastinal angiomyolipoma

“…AMLs of the mediastinum are extremely rare (2,6). To the best of our knowledge, only 10 cases of mediastinal AML have been previously reported in the English-language literature (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). The present report is the first description of a mediastinal AML that was successfully treated using video-assisted thoracoscopic surgery (VATS).…”

“…The tumors were incidentally found in four patients (1,4,6,9). The remaining six patients had symptoms such as dyspnea, chest pain, dry cough, and palpitation (2,3,5,7,8,10). These symptoms varied depending on the location and size of the tumor.…”

“…Extrarenal AMLs are considered to be multifocal lesions rather than metastases. This multicentricity of AMLs is caused by either the congenital presence of cell precursors in multiple sites or a form of benign metastases similar to that in patients with benign metastasizing leiomyoma (3,5,10). Classic AMLs are sporadic in 90% of cases.…”

“…AMLs are benign mesenchymal tumors composed of an admixture of fat, smooth muscle, and abnormal blood vessels, and the ratio of these components varies among individual patients (1)(2)(3). AMLs are usually found in the kidney.…”

“…An angiomyolipoma (AML) is a benign tumor characterized by the presence of mature or immature fat tissue, thickwalled blood vessels, and smooth muscles (1)(2)(3). An AML usually occurs in the kidney as an isolated phenomenon or as part of the syndromes associated with tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM) (4,5).…”