Extended forequarter amputation of a pediatric chest wall tumor with free flap reconstruction, targeted muscle reinnervation, and 3D-printed model guidance: a case report

Pediatric chest wall tumors are rare, with limited cases documented in the literature. This report presents a rare case of a primitive myxoid mesenchymal tumor of infancy (PMMTI) in a 2-month-old male. The tumor’s rarity, aggressive invasion into the chest wall, and patient’s age posed significant challenges in determining an optimal treatment plan that balanced complete resection with future developmental considerations. After neoadjuvant chemotherapy, the patient underwent an extended forequarter amputation (EFQA) by a multidisciplinary team of pediatric, plastic, and orthopedic surgeons. The surgery achieved complete tumor removal, with no recurrence observed at the 18-month follow-up. To our knowledge, this represents the first documented case of EFQA in an infant. A 3D-printed model of the tumor and surrounding anatomy was utilized during surgical planning. This case underscores the value of interdisciplinary collaboration in complex pediatric oncology and highlights the growing role of advanced modeling technologies.