Unusual presentation of GIST associated with type 1 neurofibromatosis

ABSTRACT Introduction and importance: Type 1 neurofibromatosis (NF1) is an autosomal dominant disorder caused by NF1 gene mutation, which is associated with several types of tumors. GIST is an intestinal stromal tumor arising from interstitial cells of Cajal in the intestine. GIST is one of the neoplasms seen in NF1 and usually affects elderly individuals with a median age around 60-65 years but rarely occur in children, adolescent and young adults. Case presentation: An 18-year-old male patient presented to our hospital with abdominal swelling of one-year duration. He also has multiple skin nodules and café au lait spots all over his body. Objectively, the abdomen is grossly distended; with a palpable non-tender mobile mass above the umbilicus measuring 20 × 15 cm. CT imaging of the abdomen and histologic examination of the skin lesion was done. The diagnosis of GIST was made and surgical resection followed by adjuvant therapy with imatinib was given. Clinical discussion: Patients who have a gene mutation in NF 1 have a high probability (7 %) of developing GIST and mostly occur in the small intestine, whereas our finding was solitary GIST localized to the stomach. NF 1-associated GISTs are very rare and account for <5 % of all GISTs. The standard therapy for GIST is surgical resection of the tumor. Targeted therapy with tyrosine kinase inhibitors is an effective adjuvant therapy in patients harboring KIT/PDGFRA mutation. Conclusion: The incidence of GIST is higher in NF1 patients than in the general population. The definitive diagnosis of GISTs preoperatively is usually challenging and is usually confirmed by immunohistochemistry. NF1-associated GISTs are mainly treated with surgery and have limited response to tyrosine kinase inhibitors. Highlights