Transverse colon schwannoma treated by endoscopic mucosal resection: A case report

Abstract

Abstract. Gastrointestinal (GI) schwannoma is one of the rarest tumors of the GI tract. We herein describe the case of a 70-year-old female patient who presented for surveillance colonoscopy. The examination detected a 1-cm polyp that was removed by snare cautery polypectomy. Immune and histochemical staining revealed spindle cells that were positive for S-100 and vimentin, but negative for CD34 and smooth muscle actin, consistent with GI schwannoma. This case is noteworthy as GI schwannomas usually present in the stomach, making the finding of a colonic schwannoma of clinical interest. Furthermore, the present case was treated by removing the tumor endoscopically, in contrast to more invasive methods. IntroductionGastric schwannoma is slow-growing mesenchymal neoplasm that originates from Schwann cells (1). This is a rare subgroup of gastrointestinal stromal tumors (GISTs), which have low malignant potential, and are clinically distinct from other non-epithelial tumors of the gastrointestinal (GI) tract, including leiomyoma, leiomyosarcoma and GI autonomic neurogenic tumors. GI schwannomas account for ~2-6% of all submucosal tumors, and ~60-70% occur within the stomach (2). While this type of tumor rarely occurs in the bowel, schwannomas may develop in any anatomical region. While the majority of schwannomas are benign, it is important to accurately identify these tumors as they may mimic other malignant lesions of the GI tract. This report presents a case of a schwannoma found at the transverse colon upon surveillance colonoscopy, which was treated by endoscopic mucosal resection. Case reportA 70-year-old female patient was referred by her primary care physician for surveillance colonoscopy in January 2017. The patient reported no major symptoms, but complained of occasional episodes of diarrhea over the past month. The patient was a non-smoker and non-drinker, and review of the systems was negative for any weight loss. The finding on physical examination were unremarkable. The vital signs were stable, and the laboratory results were within normal limits. The patient underwent a colonoscopy, which revealed evidence of moderately severe diverticulosis in the sigmoid and descending colon. A single polyp, measuring 1 cm in size, was identified in the transverse colon. Saline was injected at the base to raise the polyp prior to removal (Fig. 1A). The polyp was completely removed by snare cautery polypectomy. To control bleeding, 2 clips were applied (Fig. 1B). Histological examination of the polyp showed a solid mass with peripheral colonic mucosa ( Fig. 2A). Higher resolution revealed fascicles of spindle cells exhibiting nuclear palisading ( Fig. 2B and C). Immunohistochemistry was positive for S-100 and vimentin, but negative for CD34 and smooth muscle actin, consistent with GI schwannoma. The patient made a good postoperative recovery. Consent was obtained from the patient regarding the publication of the case details and associated images. DiscussionGI schwannoma is an extremely rare intestinal mesenchymal tu...

Ulcerated gastric leiomyoma causing massive upper gastrointestinal bleeding: A case report

“…True leiomyomas are strongly and diffusely positive for desmin and smooth muscle actin (7). Additionally, true leiomyomas and schwannomas stain negative for CD117 and CD34, while GISTs are positive for these markers (9,10). Leiomyomas tend to occur in younger patients compared with GISTs (7).…”

Laparoscopic Resection of the Schwannoma of the Colon: Case Report and Review of the Literature

“…Although schwannoma is a benign tumor with slow growth, it may show malignant transformation if left untreated. It causes symptoms such as abdominal pain, obstruction and rectal bleeding caused by other polypoid lesions (5). In our case, it was detected in a patient who was examined due to anemia and no similar case has been reported in the literature.…”

“…They are CD117 (KIT), CD34, CK5, spinal muscular atrophy and desmin negative. They generally show positive staining for S100 protein and vimentin (5). Having a Ki-67 proliferative index of ≥5% and tumor diameter greater than 5 cm increases the probability of malignancy.…”

Rare Case of a Transverse Colon Schwannoma

“…They stain negative for several markers that help differentiate these tumors from other mesenchymal cells such as DOG1 (Figure 6), SMA, desmin, CD 117, p53, CD-34 and c-kit [10,12]. Most GISTs are S-100 negative, but CD-34 and c-kit positive [10,[13][14][15][16].…”