The first case of combined pancreatic neuroendocrine tumour and neuroendocrine carcinoma

Abstract

Pancreatic neuroendocrine neoplasms are currently thought to originate from distinct progenitor cells that cannot differentiate into each other. We present the first reported case of a combined pancreatic neuroendocrine tumour and neuroendocrine carcinoma in a 58-year-old man who was investigated for abdominal pain and constipation. Imaging revealed a large left upper quadrant mass infiltrating the pancreatic body and tail, splenic hilum, and posterior stomach wall, with five hepatic metastases. This was treated with neoadjuvant and adjuvant chemotherapy, debulking surgery, and lutetium-177-DOTATATE peptide receptor radionuclide therapy. This case emphasises the importance of molecular imaging, meticulous microscopic examination, and multidisciplinary discussion for accurate diagnoses, improved prognostication, and efficacious treatment.

Figure 1

FDG and DOTATATE PET/CT of the mass. (a) Intensely FDG-avid mass with patchy regions of relative photopenia and necrosis. (b) Heterogenic DOTATATE uptake with poor uptake in the FDG avid components at the inferior aspect of the pancreatic mass and superior-posteriorly to the stomach.

Figure 2

Macroscopic appearance of the tumour. (a) Distal pancreatectomy, splenectomy, partial gastrectomy, and splenic flexure specimen. (b) 190 × 170 mm solid lesion mostly cream and yellow with a hemorrhagic and necrotic nodule (arrow).

Figure 3

Microscopic appearance of the tumour. (a) Hematoxylin and eosin (H&E) stain at 20× magnification of both the NET (right) and NEC (left) components. (b) Ki-67 immunostain at 20× magnification of both the NET and NEC components. (c) H&E stain at 200× magnification showing well differentiated NET with mild cytological atypia and low mitotic activity. (d) H&E stain at 200× magnification showing NEC with large pleomorphic cells and high mitotic rate.