Neural and neurogenic tumours of the gastroenteropancreaticobiliary tract

Abstract

Neural lesions occur uncommonly in the gastroenteropancreaticobiliary tract. However, due to the growing number of screening colonoscopy procedures, polypoid neural lesions of the colon are being recognised increasingly and range from benign tumours to high-grade malignant neoplasms. Morphological variability of neural tumours can be wide, although some entities share pathological features, and, as such, these lesions can be diagnostically challenging. We review the spectrum of pathology of neural tumours in the gastroenteropancreaticobiliary tract, with the goal of providing a practical approach for practising surgical pathologists.

Benign epithelioid peripheral nerve sheath tumour arising in the rectum: A cytological and histological description

“…MBENSTs are rare lesions described only relatively recently by Lewin et al and have since been described by some authors to be analogous to epithelioid schwannomas of the soft tissue. Their overlapping clinicopathologic features renders its distinction difficult, with both tumours being unencapsulated and composed of predominantly epithelioid cells with intranuclear inclusions . Review of the cytologic sample for our case demonstrates good correlation between the cytologic and histologic appearance, with the presence of epithelioid cells containing intranuclear pseudoinclusions providing a good clue for this diagnosis.…”

“…A number of differential diagnoses need to be considered and include other benign neurogenic tumours of the gastrointestinal tract, gastrointestinal stromal tumour (GIST), leiomyoma, carcinoma, and melanoma . Mucosal Schwann cell “hamartoma” was first described by Gibson et al as a benign neurogenic tumour which is not associated with inherited syndromes such as NF1 .…”

“…Mucosal Schwann cell “hamartoma” was first described by Gibson et al as a benign neurogenic tumour which is not associated with inherited syndromes such as NF1 . These tumours typically show a diffuse, bland spindle cell proliferation within the lamina propria, which show strong and diffuse S100 staining . The presence of an epithelioid component as well as extension into the submucosa would favour BEPNST .…”

“…The presence of an epithelioid component as well as extension into the submucosa would favour BEPNST . Other benign neurogenic tumours such as neurofibroma or perineurioma typically have sufficient distinctive characteristics to enable differentiation from each other . Distinguishing BEPNSTs from carcinomas and melanomas is usually not a difficult task, given its differing immunophenotype and the presence of atypia, mitoses or necrosis .…”

“…Within this group of tumours, a subset comprises cells with an epithelioid morphology, which was initially described in 2005 by Lewin et al and termed mucosal benign epithelioid nerve sheath tumour (MBENST) . Given its overlapping clinicopathological features, it has since been described by some authors to be analogous to epithelioid schwannomas arising in soft tissue locations . Regardless of terminology, these tumours behave in a benign fashion following surgical removal.…”