Cystic Pancreatic Neuroendocrine Tumor: A Diagnostic Dilemma

Abstract

Pancreatic neuroendocrine tumors are typically solid neoplasms but in rare instances may present as cystic lesions. Preoperative diagnosis of a cystic pancreatic lesion is challenging and requires a multidisciplinary and multimodal approach. We hereby describe an elderly female who came with complaints of abdominal lump. Radiologically, it appeared to be a pancreatic hydatid cyst located at the head of the pancreas, following which resection was done. Histopathological study of the lesion turned out to be a cystic pancreatic neuroendocrine tumor. Thus, we present this unique case due to its rarity and diagnostic challenge.

Keywords: chromogranin; cystic lesion; neuroendocrine tumor; pancreas; synaptophysin.

Fig. 1

( A ) Gross image of solid-cystic pancreatic mass with a single central unilocular cyst; ( B ) gross image of opened cyst with a smooth and shiny internal surface.

Fig. 2

( A ) Well-circumscribed, encapsulated tumor with rim of normal pancreatic parenchyma at the periphery ( arrow ) (H&E 100× ); ( B, C ) central cystic area delineated by fibrocollagenous tissue from the layer of neoplastic cells arranged in sheets (H&E 100× ); ( D ) cellular tumor composed of monotonous population of medium-sized polygonal cells (H&E 200× ); ( E ) IHC staining: synaptophysin positive (100× ); ( F ) IHC staining: low Ki67 proliferative index (200× ). IHC, immunohistochemistry.