Clin Endosc.  2018 Nov;51(6):587-590. 10.5946/ce.2018.050.

A Rare Duodenal Subepithelial Tumor: Duodenal Schwannoma

• Kahng DH
• Kim GH
• Park SG
• Lee SJ
• Park DY

• KMID: 2430403
• DOI: http://doi.org/10.5946/ce.2018.050

Abstract

Schwannomas are uncommon neoplasms that arise from Schwann cells of the neural sheath. Gastrointestinal schwannomas are rare among mesenchymal tumors of the gastrointestinal tract, and only a few cases have been reported to date. Duodenal schwannomas are usually discovered incidentally and achieving a preoperative diagnosis is difficult. Schwannomas can be distinguished from other subepithelial tumors on endoscopic ultrasonography; however, any typical endosonographic features of duodenal schwannomas have not been reported due to the rarity of these tumors. Immunohistochemistry is essential to distinguish schwannomas from gastrointestinal stromal tumors and leiomyomas. We report a case of duodenal schwannoma found incidentally during a health check-up endoscopy. On endoscopic ultrasonography, this tumor was suspected as a gastrointestinal stromal tumor; therefore, the patient underwent laparoscopic wedge resection of the tumor. Histopathology and immunohistochemistry confirmed that the duodenal lesion was a benign schwannoma.

Keyword

Duodenum; Endosonography; Schwannoma

MeSH Terms

Diagnosis
Duodenum
Endoscopy
Endosonography
Gastrointestinal Stromal Tumors
Gastrointestinal Tract
Humans
Immunohistochemistry
Leiomyoma
Neurilemmoma*
Schwann Cells

Figure

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  Fig. 1. (A) Upper endoscopy reveals a subepithelial mass covered by the normal mucosa on the duodenal bulb. (B) On endoscopic ultrasonography, the mass is a 1.5×0.7 cm sized heterogeneously hypoechoic mass with marginal haloes originating from the muscularis propria layer.

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  Fig. 2. Abdominopelvic computed tomography scans show a 1.5×1.0 cm sized homogenously-enhancing mass in the anterior wall of the duodenal bulb (arrow). (A) Axial section view. (B) Coronal section view.

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  Fig. 3. (A) The resected tumor is an intramural, solid, yellowish-to-white mass on cross section. (B) Microscopically, the mass is composed of spindle cells with wavy nuclei. Mild nuclear atypia are seen, but the mitosis count is less than 5/50 high-power fields (hematoxylin and eosin stain, ×200). Immunohistochemically, the tumor cells are strongly positive for S-100 protein, ×400 (C), but negative for smooth muscle actin, ×400 (D), CD34, ×400 (E), and c-kit, ×400 (F).

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