case_images: PMC10901465_01
case_images: Feline, female, mixed breed, 2 years old, diagnosed with solid epithelioid peritoneal mesothelioma, through histopathology and immunohistochemistry. (A) Macroscopic photo of the opening of the abdominal cavity and exposure of the abdominal organs, demonstrating the omentum with multiple nodules, diffuse, sometimes coalescing, measuring 0.2 to 2 cm, firm, whitish, and irregular (arrows); (B) Macroscopic photo showing caudal lung lobes with multiple whitish, firm, millimetric nodules in the parenchyma (circles); (C) Photomicrograph of one of the nodules in the omentum showing proliferation in a solid arrangement (asterisks) of rounded to oval cells with moderate and eosinophilic cytoplasm, evident nucleolus, and moderate cellular pleomorphism. Suggestive of solid epithelioid peritoneal mesothelioma (H.E., 20x objective, 100 mum scale); (D) Anti-calretinin immunohistochemical analysis of the anterior nodule (C) showing neoplastic cells with strong cytoplasmic immunostaining (asterisks). Indicative of solid epithelioid peritoneal mesothelioma (20x objective, scale 100 mum); (E) Photomicrograph of a lung fragment with neoplastic proliferation similar to that observed in the histopathology of nodules in the omentum, characterizing metastasis of peritoneal mesothelioma (asterisk) (H.E., 10x objective, scale 100 mum); (F) Anti-calretinin immunohistochemical analysis of the previous fragment (E) showing weak cytoplasmic immunostaining (asterisks). Indicative of peritoneal mesothelioma metastasis (40x objective, scale 50 mum).
case_images: bjvm-46-e004523-g01.jpg
case_images: PMC10901465_01_bjvm-46-e004523-g01.jpg
case_images: gf01
case_images: Furthermore, in the peritoneum, diaphragm, omentum, stomach serosa, and large intestine, multiple nodules ranging from 0.2 to 2.0 cm in diameter, coalescent, firm, whitish, and with an irregular surface were observed (Figure 1A). In the thoracic cavity, there was 6.0 mL of reddish watery fluid, and the lung parenchyma showed multiple millimeter-sized, firm, and whitish nodules, distributed diffusely throughout the organ (Figure 1B). A suggestive diagnosis of solid epithelioid peritoneal mesothelioma was assigned (Figure 1C). As for the anti-calretinin antibody, strong cytoplasmic immunostaining was observed in > 75% of the fragment for the omental nodules (Figure 1D). Lung metastasis was identified after histopathological analysis (Figure 1E), and failed cytoplasmic immunostaining for anti-calretinin antibodies was observed in < 25% of the lung fragment (Figure 1F).