Malignant extra-renal rhabdoid tumor with unusual presentation: A report of two cases.

Malignant extra-renal rhabdoid tumor (MERT) is a rare highly aggressive tumor that occurs in young children with the very poor clinical outcome. The tumor is characterized by a diffuse proliferation of "rhabdoid cells," which are round or polygonal with eccentric nuclei, prominent nucleoli, and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies. However, rhabdoid cells are also seen in certain other soft tissue sarcomas such as proximal-type epithelioid sarcoma, rarely synovial sarcoma, and extra-skeletal myxoid chondrosarcoma. Because of its poor prognosis and histomorphological similarities with other soft tissue tumors, an accurate diagnosis is required using a wide immunohistochemical panel. Very few cases of MERT have been reported in the literature and to our knowledge none in the supra-glottis area. Due to the rarity and poor outcome of this tumor, we are reporting two cases of MERT.