Gastric perineurioma detected in routine endoscopy biopsy practice: case report and review of clinico-pathological findings in the literature.

Perineuriomas are soft tissue neoplasms composed almost entirely of cells resembling perineurium and their occurrence in gastrointestinal tract is quite rare, with most of reported cases occurring in the colon. No more than 12 cases of gastric perineurioma have been reported to date, and the diagnosis in a routine endoscopy biopsy service can be challenging given the broad differentials of a bland-looking spindle cell proliferation in gastric mucosa. Here we present a case of a gastric perineurioma in a 39-year-old woman detected in routine endoscopy biopsy where a high degree of suspicion of the pathologist and targeted immunohistochemical investigations for perineurial markers EMA and GLUT1 allowed the correct diagnosis. Reviewing the literature, it appears that gastric perienuriomas most commonly occur in mid-age females and are often detected in routine endoscopies, with appearance of a benign-looking mid-sized sessile polyp. Special attention is needed to discriminate with GIST to avoid inappropriate further investigations and overtreatment. Moreover, we speculate that these lesions are likely underrecognized in busy routine gastrointestinal biopsy service, as most are probably dismissed as benign mesenchymal polyps/submucosal proliferations after exclusion of GIST or are misdiagnosed as inflammatory fibroid polyp in the case of CD34 positivity. However, the case presented demonstrates that, in light of the apparently typical occurrence in mid-aged females with endoscopic impression of benign polyp of the body, general pathologists of routine biopsy services should also have a high degree of suspicion and maybe add a perineural marker to their panel.