Solitary Schwannoma of the Colon: Report of Two Cases

Abstract

Some patients with gastrointestinal schwannoma (GIS) have been previously reported in the literature. However, GIS of the colon is quite rare. In addition, it is sometimes difficult to differentiate neurogenic tumors from other soft tissue tumors. We herein describe two cases of schwannoma of the colon, while also reviewing the relevant Japanese literature. The first case, a 73-year-old woman underwent a sigmoidectomy with lymph node dissection following the diagnosis of submucosal tumor. In the second case, a submucosal tumor was located in the cecum of a 44-year-old man. An endoscopic tumor resection was performed in the second case. The resected tumors measured 3.6 and 1.0 cm in maximal diameter, respectively. Microscopically, the tumors consisted predominantly of spindle-shaped cells that proliferated in an interlaced fashion. Mitosis was rarely seen in these tumors. Immunohistochemically, the tumor cells were strongly positive for S-100 protein, weakly positive for glial fibrillary acidic protein, and negative for CD34, alpha-smooth-muscle actin, and cytokeratin (CAM 5.2) in both cases. The tumors in the two cases were both diagnosed to be benign schwannoma of the colon. In general, schwannoma of the gastrointestinal tract is considered to be benign and should therefore be distinguished from other spindle-cell tumors or malignancies. Once diagnosed as schwannoma, extensive surgery should be avoided. Actually, such patients tend to show a good postoperative course with no evidence of recurrence.

Differentiation between gastrointestinal schwannomas and gastrointestinal stromal tumors by computed tomography

“…The head and neck region is the most prevalent location for schwannoma to occur; they are rarely observed in the gastrointestinal tract (1). Conventional schwannoma usually arise from peripheral skin nerves and connective tissue, whereas gastrointestinal schwannoma tumors are derived from Schwann cells of the Auerbach's plexus within the gastrointestinal tract wall (1)(2)(3) and were first reported by Daimaru et al in 1988 (1). As benign mesenchymal tumors, schwannomas only account for 1-2% of alimentary tract mesenchymal tumors (2,3).…”

Abdominal Schwannomas: Case Report With Literature Review

“…24,25 They usually appear as submucosal lesions, indistinguishable from other mesenchymal tumors. Furthermore, being typically hard and solid tumors, attempts to obtain good biopsy samples are often technically challenging, 26 as was the case with our patients. EUS examination is a useful tool in the preoperative assessment of gastrointestinal submucosal tumors.…”

Isolated Colonic Schwannoma in the Ascending Colon: A Case Report and Literature Review of Schwannomas in the Large Intestine

“…There is no gender predilection in the incidence of colonic schwannomas and they most commonly appear after the sixth decade of life (4). Although usually asymptomatic, colonic schwannomas may cause clinical symptoms such as bleeding, constipation, and anal pain depending on the size and location (2,5).…”

“…Schwannomas of the gastrointestinal tract are relatively rare and are known to be separate entities from conventional schwannomas which originate in soft tissue or the central nervous system (1). Of all submucosal tumors in the gastrointestinal tract, only 2% to 6% have been reported as schwannomas (2). Most gastrointestinal schwannomas occur in the stomach.…”