Background: To our knowledge, the distribution and reactivity pattern of neural cell adhesion molecule (NCAM/CD56) in GI stromal tumours (GIST) and their mesenchymal mimics have not been investigated in the KIT era. Methods: We analysed a total of 275 histologically and immunohistochemically well characterised primary and metastatic intra-abdominal mesenchymal lesions by conventional Immunohistochemistry, with emphasis on GIST and GI smooth muscle neoplasms. Results: CD56 expression was seen in 18/21 (86%), 4/5 (80%), 26/34 (76%), and 32/168 (19%) of primary GI leiomyomas, schwannomas, leiomyosarcomas, and GISTs, respectively. Reactivity in GISTs was mostly focal. Of 6% strongly staining GISTs, 71% were either malignant clinically or assigned a high risk prognostic group. CD56 expression in GISTs varied greatly with histologic type (seen in 50%, and 7% of epithelioid and spindled GISTs, respectively) and anatomic site (in 33%, 10%, 1%, and 0% of rectal, gastric, small intestinal and oesophageal GISTs, respectively). A variable, but inconsistent expression was seen in miscellaneous lesions including dedifferentiated liposarcoma, abdominopelvic PEComas, myo/fibroblastic sarcoma and "MFH". Mesenteric fibromatoses, angiosarcoma/Kaposi sarcoma, reactive tumefactive fibrogenic lesions and 12 of 13 primary anorectal and oesophageal melanomas were negative. Conclusion: Our results confirmed the ubiquity and non-specificity of CD56 as a neurogenic marker. Except for a subset of epithelioid gastric and high-grade rectal lesions, CD56 expression is rare in GISTs, contrasting with leiomyomatous and neurogenic neoplasms. CD56 plays a limited role in the differential diagnosis of GIST. Its potential role as a marker of adverse outcome in GISTs remains to be further investigated.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.