Laparoscopic Resection of Appendiceal Schwannoma

Abstract

Background Schwannoma arises from Schwann's cell of the neural sheath. Schwannoma of the large intestine, particularly of the appendix, is rare. We report a case of appendiceal schwannoma resected using laparoscopic surgery. Case Presentation A 75-year-old man was referred to our hospital for abdominal fullness and nausea since 2 months. Abdominal CT revealed a well-demarcated oval mass of 25 mm at the tip of the appendix. Contrast-enhanced CT revealed a lesion with gradually enhanced contrast from the arterial phase to the equilibrium phase. Abdominal US revealed a well-demarcated hypoechoic tumor. Preoperative diagnosis indicated appendiceal mesenchymal or neuroendocrine tumor. Ileocecal resection with D3 lymph node dissection was performed. Pathological and immunohistochemical findings confirmed the diagnosis of appendiceal schwannoma. Conclusions For determining the surgical procedure of nonepithelial tumor of the appendix, preoperative diagnosis of mesenchymal or neuroendocrine tumors is required. However, appendiceal schwannoma is extremely rare, and its characteristic findings have not yet been established. Accumulating cases of appendiceal schwannomas is necessary for improving imaging diagnosis and surgical treatment.

Appendiceal schwannoma presenting as acute appendicitis

“…Schwannomas of the large intestine are very rare. However, the incidence of accidental discovery of schwannomas of the large intestine has increased with the development of endoscopic examination techniques [5] . Nonetheless, appendiceal schwannomas are extremely rare, with only a few cases reported [ 2 , 5 , 6 ].…”

“…However, these tumors are difficult to distinguish despite advances in imaging. Recently, endoscopic ultrasonography (EUS) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) have improved the diagnosis of gastrointestinal submucosal tumors [5] .…”

“…Differential diagnoses of gastrointestinal schwannomas include GIST, leiomyomas, and NET G1. There are reports that on EUS, gastrointestinal mesenchymal tumors (schwannoma, GIST, and leiomyomas) originate in the fourth layer (muscularis propria), and NET G1 originates from the second to third layer (lamina propria–submucosa) [ 5 , 10 ]. However, we could not distinguish gastrointestinal mesenchymal tumors using radiological images alone.…”

“…Besides, the effects of chemotherapy and radiotherapy remain unclear. Lymph node dissection is not recommended for gastrointestinal schwannoma [ 5 , 10 ].…”