April 2022 – Gastroenterology Pathology

MYC.

The neoplastic cells coexpress trypsin and neuroendocrine markers without morphologically distinct acinar or neuroendocrine carcinoma components. This neoplasm is best classified as a mixed acinar and neuroendocrine carcinoma (amphicrine type) and is considered a subtype of acinar carcinoma due to shared clinical behavior and genomic features. MYC alterations are present in approximately 55% of pure acinar carcinomas but have been identified in all mixed acinar-neuroendocrine carcinomas investigated. While not associated with a prognostic difference, MYC alterations may play a role in acinar-neuroendocrine differentiation.

TP53, RB1, and KRAS alterations are associated with pancreatic neuroendocrine carcinomas.

References

1. Acinar cell carcinoma. In: WHO Classification of Tumours of the Digestive System. 5th ed. IARC Press. 333-335, 2019.
2. La Rosa S, et al. c-MYC amplification and c-myc protein expression in pancreatic acinar cell carcinomas. New insights into the molecular signature of these rare cancers. Virchows Arch. 2018 Oct;473(4):435-441.
3. Pancreatic neuroendocrine neoplasms. In: WHO Classification of Tumours of the Digestive System. 5th ed. IARC Press. 343-346, 2019.