PMC6648213_01
Axial CT scan of the abdomen in case 1 with intravenous contrast revealing a complex 2.3 cm pancreatic head lesion (arrow). CT, computed tomography.
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Follow-up with a dedicated pancreatic triple phase computed tomography (CT) was performed, which revealed a 2.3 cm hypodense mass in the pancreatic head with a 4 mm enhancing component in the posterior aspect of the lesion with internal septations (Fig. 1).
H&E-stained sections of UCOGC. (A) Low-power view demonstrating a fairly well-circumscribed tumor nodule surrounded by a rim of desmoplastic stroma (arrow), which abuts adjacent benign pancreas. Hemorrhage is observed within the tumor (arrow), 20x . (B) Central hemorrhage and necrosis give the appearance of a condensation of hyperchromatic nuclei toward the periphery of the nodule, 100x . (C) Multiple mitotic figures, including one bizarre pentapolar mitosis (arrow), are observed within a background of multinucleated giant cells and microscopic hemorrhage. Malignant cells demonstrate marked nuclear pleomorphism and hyperchromasia, 200x . (D) High-power view demonstrating an additional atypical mitotic figure surrounded by multinucleated giant cells (arrows) with a dense cytoplasm. Over 20 distinct nuclei can be observed within a single cell, 400x . H&E, hematoxylin and eosin; UCOGC, undifferentiated carcinoma with osteoclast-like giant cells.
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Microscopically, the tumor was well circumscribed with a pushing border, nodularity, and hemorrhage, and was composed of sheets of markedly pleomorphic mononuclear cells with interspersed non-neoplastic osteoclast-like (CD68+) multinucleated giant cells (Fig. 2A).
PMC6648213_02
Axial CT scan of the abdomen in case 2 with intravenous contrast showing an ill-defined pancreatic head mass (arrow) that measures 3.6 x 3.6 cm. There is associated pancreatic ductal dilatation with abrupt cutoff at the level of the mass. The mass abuts the superior mesenteric vein and there is attenuation of the main portal vein and SMV at the confluence related to the mass. SMV, superior mesenteric vein.
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A CT scan described a pancreatic head mass measuring 3.6 cm x 3.6 cm, which did not extend inferior to the third part of the duodenum, but it seemed to abut the superior mesenteric vein and possibly the main portal vein as well (Fig. 3).
H&E-stained sections demonstrating clear cell features. (A) Low-power view demonstrating irregular malignant glands with surrounding desmoplastic tumor stroma. The normal lobular architecture of the pancreas is lost, 5x . (B) Angulated malignant glands are lined by epithelial cells with hyperchromatic basal to central nuclei of varying sizes and variable amounts of foamy to clear cytoplasm (arrows). Single malignant cells are present within the stroma, 100x . (C) Malignant cells are seen invading between an arteriole (black arrow), a nerve (white arrow), and adjacent benign pancreas (asterisk), 100x . (D) Similar histopathologic findings are observed in metastatic tumor glands seen in the subcapsular sinus of a peripancreatic lymph node (arrow), 100x .
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IIB (AJCC 8th edition, ypT2N1M0) with poor treatment response and positive uncinate margin. Interestingly, histology revealed PDAC with clear cell features (Fig. 4).