An 18-year-old girl has an 8 cm solid and cystic mass in the tail of the pancreas. Biopsy shows uniform cells forming sheets with pseudopapillary structures around delicate vessels, with degenerative change away from the vasculature. Immunohistochemistry shows strong nuclear and cytoplasmic beta-catenin staining. This tumour:

• A Has an excellent prognosis after complete surgical excision ✓
• B Is a highly aggressive malignancy requiring neoadjuvant chemotherapy
• C Shows KRAS mutation in over 90% of cases
• D Arises from multipotent pancreatic stem cells and secretes vasoactive intestinal peptide

Explanation

Solid pseudopapillary neoplasm occurs almost exclusively in young women and shows activating CTNNB1 (beta-catenin) mutations, giving abnormal nuclear staining along with loss of E-cadherin expression. Despite its size and worrisome appearance it behaves indolently, and complete surgical resection is curative in the great majority. KRAS mutation characterizes ductal adenocarcinoma, not this entity, and VIP secretion belongs to VIPoma among pancreatic neuroendocrine tumours.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.