Extra-Renal Rhabdoid Tumor: A Rare Malignant Tumor in Child about Four Cases

The rhabdoid tumor is a rare and aggressive tumor of pediatric population. Their grouping within a single entity is recent, following the discovery of a bi-allelic inactivation of the HSNF5/INI1 tumor suppressor gene in tumor cells. The present study aims to highlight the different epidemiological, clinical, histopathological, and immunohistochemical, and genetic features of extra-renal rhabdoid tumors in children. We present a case series of extra-renal rhabdoid tumor (ERRT), recorded at the Department of Pathology of University Hospital Center of Hassan 2 of Fez, in Morocco. From 2014 to 2022, four cases of extra renal rhabdoid tumor have been recorded in our department, their ages ranged from 2 to 7 months, and they were all boys. The sites most affected were the soft tissues. The histological analysis of all patients’ specimens demonstrates the presence of rhabdoid cells. In the immunohistochemistry study, we noted a complete loss of INI-1 staining by tumor cells. However, the tumor cells have cytoplasmic positivity with a dot-like pattern for epithelial membrane antigen (EMA), CK AE1/AE3, and vimentin. Two of our patients were treated with chemotherapy, and 2 patients underwent surgery and then chemotherapy. The evolution was lethal in all cases. Rhabdoid tumor is a rare and aggressive tumor that occurs in children. It should be included in the differential diagnosis of rounds cells tumors of children and thought about in front of any aggressive isolated tumor. It is a challenging diagnosis for pathologists, especially with tiny biopsy material, or minor rhabdoid components.