case_images: PMC10858661_01
case_images: Macroscopic appearance of a metastatic pancreatic carcinoma with neuroendocrine differentiation in an adult cat: (a) in situ evaluation of the abdominal cavity evidenced carcinomatosis, mild hydroperitoneum, accentuated fibrinous peritonitis and a solid irregular mass, topographically arising from mesenteric lymph nodes and replacing the epiploon, and adhered to the spleen; (b) numerous white solid plaques, multifocal to coalescing, 0.5-2.0 cm in size, spread throughout the serosa of the diaphragm; (c) the pancreas was marked by severe atrophy (arrow) and had multiple white, well-delimited plaques neoformation, 0.2-0.5 cm in size, located in the pancreatic head and tail (arrowhead); (d) multiple white solid nodules, 0.5-1.0 cm in size, spread throughout the mesentery (arrow); and (e) dissected irregular mass of panel (a), topographically arising from the mesenteric lymph nodes and replacing the epiploon. Bar = 1.0 cm
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case_images: The necropsy examination showed mild hydroperitoneum and accentuated fibrinous peritonitis, and in the abdominal cavity there were numerous multifocal to coalescent firm nodules spread throughout serosa (Figure 1a and b). The pancreas was severely atrophied and had multiple white, well-delimited plaques neoformation, 0.2-0.5 cm in size, located in the pancreatic head and tail (Figure 1c). Metastases were observed in the mesenteric lymph nodes, omentum, diaphragm, mesentery and peritoneal serosa (Figure 1d). An in situ evaluation of the abdominal cavity evidenced a solid irregular mass, topographically arising from the mesenteric lymph nodes and replacing the epiploon, and adhered to the spleen (Figure 1e).
case_images: Pancreatic carcinoma with neuroendocrine differentiation in a domestic cat. (a) Expansive proliferation, unencapsulated, compresses the remainder of the non-neoplastic pancreatic parenchyma. Hematoxylin and eosin (H&E), x 20. (b) Proliferation is composed of polygonal cells arranged predominantly in a glandular pattern, with acinar structures in various sizes, separated by thin fibrous stroma. H&E, x 20. (c) Higher magnification demonstrates an epithelial neoplastic cell population with well-defined, abundant eosinophilic and finely granular cytoplasm. The nucleus is round with coarse chromatin and conspicuous nucleoli. Filling the central gap of the acini is an amount of homogeneous, eosinophilic material. H&E, x 40. (d) Section of the abdominal wall demonstrates a lymphatic vessel with a neoplastic embolus. H&E, x 20
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case_images: Microscopically, the pancreatic nodule consisted of an expansive proliferation, unencapsulated, composed of polygonal cells arranged predominantly in glandular pattern, with large acinar structures that usually present variable amounts of homogeneous eosinophilic material filling the central gap of these structures (Figure 2a and b). The neoplastic cells were polygonal, well-defined and had abundant eosinophilic cytoplasm (Figure 2c). Marked cell pleomorphism, anisocytosis and anisokaryosis, as well as several areas of intratumoral and peripheral lymphatic invasion (Figure 2d), intratumoral necrosis and 41 mitotic figures 2.37 mm2 in size were observed, including bizarre ones.
case_images: Immunostaining results for pancreatic carcinoma with neuroendocrine differentiation in a domestic cat: (a) neoplastic cells were diffusely positive for cytokeratin(CK)20; (b) neoplastic cells were diffusely positive for anti-pan-cytokeratin(AE)1/AE3; and (c,d) approximately one-third of neoplastic cells were positive for chromogranin A. Immunohistochemistry: 3,3-diaminobenzidine tetrachloride (DAB) for all sections and counterstained with Harris's hematoxylin, x 20
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case_images: Immunohistochemical examination revealed that neoplastic cells demonstrated a strong positivity for AE1/AE3 and CK20 (Figure 3a and b). Immunoreactivity of approximately one-third (30%) of the cells to CgA was observed, which demonstrates neuroendocrine cell labeling (Figure 3c and d).