An 87-year-old woman with a past medical history significant for invasive bladder cancer was found to have an enlarging mixed solid and cystic lesion in the body/tail of her pancreas on surveillance imaging. She underwent a EUS biopsy and subsequent distal pancreatectomy. The 5.5 cm mass showed the following histology and immunohistochemical profile.
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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.
Holly Berg, D.O., MLS(ASCP)
Resident, Anatomic and Clinical Pathology
Saba Yasir, M.B.B.S.
Consultant, Anatomic Pathology
Assistant Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine and Science