Sporadic neurofibroma of transverse colon in a patient without neurofibromatosis type 1: A case report

The occurrence of sporadic colonic neurofibroma particularly in a patient without neurofibromatosis type 1 has been rarely reported. Therefore, the clinical significance of this disease has not been fully elucidated. An 81-year-old woman with a positive fecal occult blood test result was referred to our institution for the evaluation of anemia. On colonoscopy, a 50-mm submucosal tumor-like mass was found in the hepatic flexure of the colon. Superficial biopsy and boring biopsy showed unspecific granulation tissues, and immunostaining revealed that the mesenchymal tumor was negative for CD34, c-kit, desmin, and S100 protein. The patient underwent laparoscopic right colectomy with complete mesocolic excision (CME). Pathologically, the tumor was diagnosed as neurofibroma. Gastrointestinal neurofibromas are known to cause clinical symptoms. No colonic neurofibroma has been diagnosed before resection. Moreover, neurofibromas, particularly large lesions, reportedly undergo malignant transformation. Surgical extirpation with clear margins is the primary treatment, and laparoscopic surgery is considered acceptable for colonic neurofibroma and colon cancer. Based on our experience, a preoperative diagnosis was impossible for colonic neurofibroma. Laparoscopic surgery with CME is considered feasible for sporadic colonic neurofibroma.