Diagnosis and treatment of neurofibromatosis type 1 with malignant transformation and multiple gastrointestinal stromal tumors: a case report and literature review.

A 51-year-old female patient was diagnosed with neurofibromatosis type 1 (NF1) in 2000 (21 years ago). In 2015 (6 years ago), she underwent surgical resection of a mass in her right upper limb. The tumor was pathologically confirmed as malignant peripheral nerve sheath tumor (MPNST) (considering malignant transformation of neurofibroma) and neurofibroma. In 2021, she was admitted to the hospital due to urinary urgency and abdominal mass. Transvaginal ultrasound showed multiple masses in the uterus, and leiomyoma was considered. Multiple fish-like bleeding masses on the surface of the uterus, sigmoid colon and jejunum were found during the operation, and then combined gynecological and gastrointestinal surgery was performed. Postoperative pathology and immunohistochemistry (CD117, DOG-1, CD34 positive) confirmed that all masses were gastrointestinal stromal tumors (GIST)(including uterine Extra-GIST (EGIST)), and C-kit/PDGFRA gene mutation was negative. After 4 years of follow-up, there was no recurrence or metastasis of GIST and EGIST. The patient underwent 4 operations for neurofibroma in the back (including 1 reoperation for recurrence). We report a rare case of NF1 with concurrent right upper limb MPNST, jejunal GIST, and multiple EGISTs in the uterus and sigmoid colon. Despite overlapping pathological features, uterine and gastrointestinal stromal tumors differ clinically. Surgery is the primary treatment; comprehensive preoperative imaging and postoperative pathological examination are critical to prevent misdiagnosis and optimize management.