Alveolar rhabdomyosarcoma in children with histomorphological review.

Rhabdomyosarcomas (RMS) are aggressive malignant neoplasm of mesenchymal origin, related to skeletal muscle lineage. These are the most common soft tissue tumors in children. The diagnosis is made by microscopic analysis and ancillary techniques like immunohistochemistry, electron microscopy, cytogenetics and molecular biology. We encountered a case of a 03 years old child who presented with a tender, reddish, soft swelling over cheek for three weeks. The FNAC was reported as a small round cell tumor, Probably Primitive Neuroectodermal Tumor (PNET). The biopsy of tumor revealed a small round cell tumor with an alveolar pattern. Tumor giant cells were absent and mitotic figures were infrequent. Hence, differentials of alveolar rhabdomyosarcoma and PNET were rendered. Immunohistochemistry (IHC) demonstrated desmin positivity. Thus, a final diagnosis of alveolar rhabdomyosarcoma was offered.