細胞学および組織学ジャーナル

Gastric Schwannoma, an Unusual Synchronous Tumor with Renal Cell Carcinoma

Abstract

Chih-Yi Liu and Yih-Yiing Wu

Schwannomas, also called neurilemomas, are neurogenic tumors derived from Schwann cells of nerve sheath. They are relatively common in head, neck, extremities, retroperitoneum, posterior spinal roots and cerebellopontine angle, and are generally benign and slow-growing with rare recurrence or malignant transformation. However, they are rare in the gastrointestinal (GI) tract and mostly located in the stomach. Gastric schwannomas represent about 2% of the gastric mesenchymal neoplasms, and are clinically and grossly nearly indistinguishable from gastrointestinal stromal tumors (GISTs). GISTs are the major primary mesenchymal tumors of the GI tract. They have a variable malignant potential and can be coexistent with renal cell carcinomas (RCCs). In contrast, gastric schwannomas are regarded as benign and no concurrent malignancies have been documented. Here, we report a 54-year-old woman having a right radical nephrectomy for a clear cell RCC, and then received a radical subtotal gastrectomy for a gastric tumor under the impression of GIST four months later. Histopathologically, the gastric tumor was a submucosal spindle cell neoplasm with a particular peripheral lymphoid cuff. The neoplastic cells were immunohistochemically positive for S-100 protein, but negative for CD117 (c-kit), CD34, smooth muscle actin, desmin and Dog1. Eventually, the gastric submucosal tumor was confirmed to be a rare benign gastric schwannoma, which was an unusual synchronous tumor with RCC.