A rare case of Non Renal/ Non CNS malignant rhabdoid tumor originating from the omentum

Malignant Rhabdoid Tumor (MRT) is a rare and aggressive malignancy in pediatric patients. These tumors typically originate in the kidney and central nervous system (CNS). There are approximately 15 cases of non-renal/non-CNS MRT diagnosed each year in the United States, originating from the liver or other soft tissues. The development of MRT is associated with a deletion or inactivating mutation of the SMARCB1 tumor suppressor gene. The average age at diagnosis is 15 months. These tumors carry a poor prognosis due to advanced stage presentation and poor response to therapy. We present a case of a 9 year old male with symptoms suggestive of complicated appendicitis. Surgical exploration revealed the entire omentum studded with tumors and peritoneal carcinomatosis. Biopsy of the omentum and appendix confirmed the diagnosis of non-renal/non-CNS Malignant Rhabdoid Tumor. The omentum is often a site of metastasis for MRT, but is rarely a primary tumor site, as was suspected in this case.