Gastric Schwannoma mimicking gastrointestinal stromal tumors: a rare case with review of literature

Abstract

Gastric schwannoma (GS) is a rare neoplasm of the stomach. It accounts for 0.2% of all gastric tumors and is mostly benign, slow-growing, and asymptomatic. Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors and up to 60-70% of GIST occur in the stomach. Schwannoma and GIST have similar radiological and endoscopic features making it extremely difficult to differentiate them preoperatively. Differential diagnosis of these two submucosal tumors is important because of the malignant potential of GIST and the relatively benign course of gastric schwannomas. This case stresses on the importance of including gastric schwannomas in the differential diagnosis of a submucosal gastric mass as it has the ability to mimic a gastrointestinal stromal tumor, which is a leading differential diagnosis because of its common occurrence at this site.

Gastric Schwannoma: A Case Report and Literature Review

“…Their size can vary from 0.5 cm to 15.5 cm in diameter. Upon dissection, they present as a yellow, gray, pearly white, and sometimes variegated mass in case of necrosis, hemorrhage or fatty infiltration [ 5 , 8 ]. In our patient, GS was found to originate from the muscularis propria in the body of the stomach.…”

“…As in our patient, when symptomatic, they can present with abdominal pain, abdominal fullness, change in bowel habits, nausea, vomiting, hematemesis, melena and even with intussusception. They can also compress surrounding structures leading to ulceration and bleeding [ 1 , 5 , 6 ].…”

“…However, due to its submucosal location and minimal mucosal abnormality, endoscopic biopsies are mostly inconclusive as compared to EUS with fine needle aspiration (FNA) biopsy which can assist in preoperative evaluation of the tumor. Despite availability of all these modalities, the definite diagnosis of GS is made with biopsy after surgical excision of the tumor that displays an exophytic, demarcated lesion with a rubbery texture and without ulceration or calcification [ 1 , 4 , 5 , 6 ].…”

“…Under the microscope, GS appear as firm, well-circumscribed, encapsulated tumors with a spherical, ovoid or multilobed configuration, developing near the nerves without their invasion [ 5 , 8 ]. On histologic examination, GS shows a fascicular arrangement with spindle-shaped nuclei.…”

“…The stomach is the most common site of involvement, constituting 60-70% of all cases involving the GI tract while the colon and rectum represent only 3% of the cases [ 1 , 3 , 4 ]. Constituting only 4% of all benign and 0.2% of all gastric tumors, gastric schwannoma (GS) is a rare submucosal tumor that develops from Schwann cells of the Auerbach's plexus of the stomach and was first mentioned by Daimaru et al in 1988 [ 1 , 2 , 4 , 5 ]. If symptomatic, patients can experience abdominal pain, change in bowel habits, nausea, and vomiting [ 1 , 3 , 4 ].…”