Synchronous cutaneous malignant peripheral nerve sheath tumor and jejunal gastrointestinal stromal tumor and submucosal angiomyolipoma in type 1 neurofibromatosis: A case report and literature review

Rationale: Type 1 neurofibromatosis (NF1) is one of the most prevalent genetic conditions. NF1 is characterized by cutaneous plexiform neurofibromas and cafe au lait skin pigmentation, and is inherited in an autosomal dominant trait with mutation in the neurofibromin 1 gene on chromosome 17. Neurofibromin is involved in Ras proto-oncogene regulation. Accordingly, NF1 may lead to malignancies, with a lifetime cancer risk of 60%. Malignant peripheral nerve sheath tumor (MPNST) is the leading cause of mortality due to NF1. The relevance of gastrointestinal stromal tumor (GIST) in NF1 is increasingly being reported in the literature and NF1-associated GIST has been identified to have an alternative molecular pathogenesis. Patient concerns: A 62-years-old female had a 7x5cm growing back mass in the background of various sized cutaneous neurofibromas with cafe au lait spots. Computed tomography performed in the workup revealed a 4.1cm enhancing mass near the ileal mesentery. Diagnoses: NF1 affected by cutaneous MPNST of the back, and synchronous GIST and submucosal angiomyolipoma (AML) of the jejunum. Interventions: The patient underwent laparoscopic jejunal mass excision, and excision and flap coverage for the back mass owing to the suspicion of multiple MPNSTs. However, the abdominal masses were diagnosed as GIST and AML following confirmation of the immunohistochemical profiles. Accordingly, the patient was administered adjuvant radiotherapy to the MPNST after surgery. Outcomes: Symptomatic improvements were achieved, and no subsequent relapses were observed. Lessons: Although MPNST and GIST are not rare neoplasm in NF1, only 2 case reports have been published on the synchronous occurrence of these tumors. Moreover, no case report has been published on AML in NF1, except 1 renal AML in segmental neurofibromatosis. Identifying the clinical and pathologic significances of the NF1 is important to achieve improved diagnostic accuracy.