Imaging findings in a case of mixed acinar-endocrine carcinoma of the pancreas

Abstract

Mixed acinar-endocrine carcinoma (MAEC) of the pancreas is extremely uncommon. We report here a rare case of MAEC of the pancreas presenting as watery diarrhea. This is the first report in the English-language literature that describes the imaging findings of MAEC of the pancreas, including computed tomography (CT), magnetic resonance (MR) imaging, and MR cholangiopancreatography features.

Keywords: Endocrine; Exocrine; Mixed acinar-endocrine carcinoma; Pancreas.

Fig. 1

59-year-old woman presented with watery diarrhea that had persisted for two years. A. On contrast-enhanced axial CT scan during hepatic arterial phase, tail of pancreas, which is approximately half length of longest pancreatic axis, was diffusely replaced by heterogeneously hypo-attenuating mass-like lesion (arrows). Approximately 1.5-cm hypervascular nodule (open arrow) was also visible in mass. B. T2-weighted axial MR image indicates that mass (arrows) was heterogeneously hyperintense compared to normal pancreas, except for heterogeneously hypointense nodule (open arrow) in mass. C. Contrast-enhanced T1-weighted axial MR image during hepatic arterial phase showed that tumor (arrows) enhances heterogeneously with multiple well or poorly enhancing areas relative to normal pancreas. Nodule (open arrow) in mass was also found to be well enhanced. D. MR cholangiopancreatography showed that tumor (arrows) was hyperintense with multiple hypointense nodular lesions. E. Photograph of surgical specimen reveals well-demarcated, lobulate, soft-tissue mass (arrows) located at tail of pancreas. Areas of hemorrhage and focal necrosis with cystic change in mass are evident. S = spleen F. Immunohistochemistry results suggest that tumor cells are immunoactive for anti-trypsin (×200). G. Photomicrograph of mass with immunohistochemical staining showed that tumor cells are immunoactive for synaptophysin (×100).