Retroperitoneal malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1: a case report.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive sarcomas originating from peripheral nerves or nerve sheath cells. They are often associated with neurofibromatosis type 1 (NF1) and have a poor prognosis due to high rates of recurrence and metastasis. We report a case of a 30-year-old female presenting with a retroperitoneal MPNST accompanied by metastases to the right pelvic wall and left rectus femoris muscle. The patient exhibited numerous café au lait spots densely distributed across the head, neck, trunk, and extremities, consistent with clinical features of NF1. Due to the limitations of gynecological ultrasonography, the mass was initially considered to originate from the adnexal region. Surgical interventions included exploratory laparotomy, partial colectomy, partial rectal resection, retroperitoneal neoplasms resection, and colostomy; however, only palliative resection was possible due to the tumor's extensive invasion and inability to achieve clear margins. Histopathological examination, supported by immunohistochemical findings, confirmed the diagnosis of MPNST. Given the palliative nature of surgery and the short postoperative follow-up, the clinical outcome remains uncertain. This case highlights the diagnostic challenges of retroperitoneal MPNST, particularly in patients with NF1, and underscores the importance of early recognition and multidisciplinary management when curative resection is not achievable.