Diagnostic conundrum of a perineal tumour: a rectal gastrointestinal stromal tumour mimic
- Author:
Shi RUOYU
1
;
Chew Min HOE
;
Leow Wei QIANG
Author Information
1. Department of Anatomical Pathology, Singapore General Hospital, Singapore
- Publication Type:Case Report
- Keywords:
rectal;
gastrointestinal;
schwannoma;
stromal tumour;
mesenchymal
- From:The Malaysian Journal of Pathology
2017;39(3):293-296
- CountryMalaysia
- Language:English
-
Abstract:
Gastrointestinal stromal tumour (GIST) is a common mesenchymal tumour arising in the gastrointestinaltract, but not frequently encountered in the rectum. Herein, we describe a case of a rectal GISTwhich mimicked histomorphological features of a schwannoma; thus, making intraoperative frozensection evaluation challenging. Although subsequent immunohistochemistry and molecular findingsreadily confirmed the diagnosis of a GIST, we wish to draw attention to three clues that will help thepathologist steer clear of this potential diagnostic pitfall. One, GISTs are relatively more commonthan schwannomas in the rectum. Two, schwannomas usually have very little mitoses. Three,rectal GISTs commonly exhibit nuclear palisades. We also discuss the diagnostic, prognostic andtherapeutic functions of immunohistochemical and molecular investigations. As the surgical intentfor rectal GISTs is for en-bloc excision with wide margins, we surmise that the intraoperative consultshould include GIST as a possible differential diagnosis for rectal mesenchymal tumours. In view ofthe potential for neoadjuvant treatment with imatinib before surgical excision to preserve sphincterfunction, a multidisciplinary approach is recommended for establishing most effective treatmentstrategy in these rare complex cases.
