Perineurioma Diagnosed After Endoscopic Treatment of Suspected Gastric Adenocarcinoma of the Fundic Gland.

Perineurioma is a relatively rare tumor with an occasionally difficult differential diagnosis. A 63-year-old woman underwent esophagogastroduodenoscopy, which revealed a 15 mm, slightly faded, flat, and elevated lesion in the gastric body. Biopsy revealed a bundle-like proliferation of spindle-shaped cells; however, the diagnosis was unconfirmed. Endoscopic submucosal dissection was performed for diagnosis and treatment. Histopathological examination of the lesion revealed cell proliferation with short spindle-shaped and oval nuclei and little atypia in the lamina propria. Immunohistochemical examination indicated a perineurioma. Thus, when spindle-shaped cells are found on biopsy, it is necessary to consider the possibility of perineurioma.