Clinicopathologic Features of Gastric Schwannomas: A Retrospective Analysis

Gastric schwannomas are rare, benign gastrointestinal mesenchymal tumors that pose diagnostic challenges because they overlap histologically with other mesenchymal neoplasms, particularly gastrointestinal stromal tumors (GISTs). Thus, reliable diagnostic criteria are critical for distinguishing gastric schwannomas from GISTs to ensure timely, appropriate therapy. We conducted a retrospective study of patients diagnosed with gastric schwannoma at 2 institutions to evaluate the pathological features of gastric schwannomas and their distinguishing characteristics. Patient demographics, radiologic, histopathologic, and immunohistochemical features were analyzed. A total of 22 patients with a median age of 66 years (range, 36-77) were included: 7 men (32%) and 15 women (68%). The median tumor diameter was 5.3 cm (range, 1.0-10.0), and preoperative imaging suggested an initial diagnosis of GISTs in 7 patients (32%). Histologically, Verocay bodies were observed in 10 tumors (45%), vascular hyalinization in 13 (59%), discrete lymphoid aggregates in 5 (23%), and plasma cells in 8 (36%). Immunohistochemically, all tumors were positive for the gastric schwannoma markers S100 and SOX10, had variable CD34 expression, and were negative for α-smooth muscle actin and the GIST markers CD117 (KIT) and DOG1 (ANO1). Our findings aligned with previously reported demographic patterns and gastric schwannoma immunoprofiles; however, we also observed several histologic features less frequently described in the literature. Our observations refine the histopathologic characterization of gastric schwannomas and underscore the importance of thorough tissue evaluation for accurate diagnosis of this rare tumor.