Malignant Ectomesenchymoma in a 6-Month-Old: A Rare Pediatric Tumor Case Report.

Malignant ectomesenchymoma is a rare type of soft tissue tumor that contains both mesenchymal and neuroectodermal components. We present the case of a 6-month-old male with an abdomino-pelvic mass, initially diagnosed as embryonal rhabdomyosarcoma. He had poor response to chemotherapy and radiotherapy, and subsequent complete surgical resection demonstrated the tumor to be compatible with malignant ectomesenchymoma. This case highlights the diagnostic challenges, treatment complexity, and need for comprehensive histopathological evaluation in rare tumors. We aim to contribute to the limited literature and emphasize the importance of individualized, multimodal treatment approaches.