PMC5968152_01
Radiology features of the pancreatic lesion. Contrast-enhanced computed tomography (A) axial and (B) coronal image demonstrating a heterogeneously enhanced hypervascular lesion (arrow) in the head of the pancreas. (C) Endoscopic ultrasound image demonstrating the mass within the head of the pancreas (1.8 x 1.55 cm).
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F1
Contrast-enhanced computed tomography (CT) of the abdomen showed a well-circumscribed, heterogeneously enhancing lesion (1.7 x 1.5 cm) within the pancreatic head, with no dilation of the pancreatic duct or common bile duct (Figure 1). Endoscopic ultrasound revealed a well-demarcated, round, hypoechoic mass, measuring 1.8 x 1.55 cm in its largest dimension, as well as a non-dilated pancreatic duct and normal-appearing pancreatic body and tail (Figure 1).
Low-power view of an area demonstrating components of neuroendocrine tumor (upper left and lower right) and pancreatic ductal adenocarcinoma (PDAC; upper right), without a transition zone.
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F2
Fine-needle aspiration biopsy revealed uniform cells with round, regular nuclei and finely distributed chromatin without prominent nucleoli, arranged in single cells as well as in sheets and clusters, with rare groups of benign glandular epithelium (Figure 2).
Microscopic view of well-differentiated neuroendocrine tumor. (A) High-power view with tumor cells forming irregular nests and trabecular cords. (B) Immunohistochemical stain for chromogranin revealed positivity (brown) in the neuroendocrine tumor component but not in the PDAC component.
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F3
Microscopically, the majority of the tumor consisted of nests of cells that were positive for chromogranin and synaptophysin but negative for CA 19-9, consistent with a well-differentiated neuroendocrine tumor (NET) (Figure 3).
Microscopic view of well-differentiated PDAC. (A) High-power view showing infiltration of small, irregular glands with nuclear atypia and surrounding fibrous tissues. (B) Immunohistochemical stain for CA 19-9 revealed positivity (brown) in the PDAC component but not in the neuroendocrine tumor component.
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F4
These cells were positive for CA 19-9 and negative for chromogranin and synaptophysin, consistent with the diagnosis of a concurrent pancreatic ductal adenocarcinoma (PDAC) within the NET (Figure 4).