Malignant Extra-Renal Rhabdoid Tumor : Introduction
Malignant extrarenal rhabdoid tumor (MERT), rhabdoid tumor of kidney, and atypical teratoid/rhabdoid tumor of the central nervous system are a group of related high-grade tumors that share histologic features and possess identical molecular and cytogenetic abnormalities. The site distribution is as follows: kidney 20%, extrarenal (non-CNS) 45%, and CNS 35% (Source: SEER database). Rhabdoid morphology may also be seen in a variety of carcinomas, sarcomas and melanoma. The term MERT is used for tumors with a predominant rhabdoid appearance in which no other line of differentiation can be identified. This image is from an extrarenal rhabdoid tumor involving soft tissues of the neck in a 12 y/o female. It is composed of solid sheets of tumor cells with abundant eosinophilic cytoplasm. The tumor cells can be seen infiltrating skeletal muscle on the top right.