Abstract
It is sometimes challenging to differentiate between gastrointestinal (GI) mucosal melanoma and gastrointestinal stromal tumors (GISTs) because they share some similarities in histological and molecular features. In this study, we investigated their clinicopathological and molecular features. Four primary GI mucosal melanomas and 4 atypical GISTs resected from 2017 to 2019 were included. Electronic medical records and histology slides were reviewed and, if needed, immunohistochemical stainings were additionally done. Somatic mutations were analyzed using whole exome sequencing (WES) with tumors and matched normal tissues. By immunohistochemistry, GISTs were positive for CD117 (4 of 4), DOG1 (4 of 4), and CD34 (2 of 4). In contrast, melanomas were positive for CD117 (2 of 4), HMB-45 (4 of 4), Melan-A (4 of 4), and S100 protein (3 of 4). Using WES, the KIT mutation was detected in 2 of 4 GISTs and 1 of 4 melanomas, all of which showed strong CD117 immunoreactivity. PDGFRA mutation was detected in 2 of 4 GISTs but 0 of 4 melanomas. TP53, NF1, RB1, TERT, and KMT2D mutations were detected in 1 of 4 melanomas but 0 of 4 GISTs. A patient with KIT-mutated melanoma was treated with Gleevec and has remained disease-free for 1 year. GISTs and GI melanomas have a wide histopathological spectrum. Appropriate ancillary studies can be helpful for proper diagnosis and optimal treatment.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.