PMC10102469_01
Preoperative abdominal ultrasonographic study. Large, cavitated, heterogeneous mass (white arrowheads) arising from the left kidney.
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F1
Abdominal ultrasonography showed a large (at least 8.7 x 12 cm), heterogeneous, cavitated mass extending cranially from the cranial pole of the left kidney and causing overall caudal displacement of the left kidney (Figure 1), as well as mild left renal lymphadenopathy (6.7 mm), diffuse peritoneal steatitis, and mild peritoneal effusion.
(A) Initial abdominal explore findings with left renal mass surrounded by omentum (right) and spleen (left). (B) Left renal mass following dissection of omental adhesions.
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F2
Abdominal explore revealed a large left renal mass (Figure 2) and mild generalized rounding and mottling of the liver.
Histopathology and immunostaining of the dog's renal cell carcinoma (A-C), accessory lung lobe neoplasm (D-F), and right caudal lung lobe neoplasm (G-I). 20X. (A) Renal cell carcinoma in which neoplastic epithelial cells are arranged in tubules, nests, and streams; hematoxylin and eosin (HE). (B) Cytokeratin immunohistochemistry (IHC) of the renal cell carcinoma: positive cytoplasmic staining of neoplastic epithelial cells. (C) Vimentin IHC of the renal cell carcinoma: positive cytoplasmic staining of neoplastic epithelial cells. (D) Accessory lung lobe neoplasm in which neoplastic cells are arranged in lepidic cords and papillary projections; HE. (E) Cytokeratin IHC of the accessory lung lobe neoplasm: moderate positive cytoplasmic labeling of neoplastic cells. (F) Vimentin IHC of the accessory lung lobe neoplasm: negative staining of the neoplastic cells. (G) Right caudal lung lobe neoplasm in which neoplastic cells are arranged in nests amongst abundant inflammation and necrosis; HE. (H) Cytokeratin IHC of the right caudal lung lobe neoplasm: strong positive cytoplasmic labeling of the neoplastic cells. (I) Vimentin IHC of the right caudal lung lobe neoplasm: negative staining of the neoplastic cells.
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F3
Histopathology of the dog's renal mass was consistent with RCC with a large central focus of cell dropout and necrosis in which the cells were arranged in tubules, nests, and streams and demonstrated moderate nuclear pleomorphism, no vascular invasion, and a mitotic count of 18 per ten 400X high-power fields (Figure 3A). Histopathology of the right caudal lung lobe lesion was consistent with a malignant neoplasm, in which a moderately demarcated neoplastic proliferation of polygonal cells was arranged in lobules and nests amongst the pre-existing pulmonary stroma (Figure 3G). The accessory lung lobe lesion was consistent with a pulmonary carcinoma in which cuboidal to columnar neoplastic epithelial cells were arranged in long anastomosing cords in a lepidic pattern and papillary projections supported by a fine fibrovascular stroma (Figure 3D). Immunohistochemistry was performed for the pulmonary lesions to further characterize the cell of origin and whether they represented primary pulmonary neoplasms or metastatic disease from the previously diagnosed RCC (Figure 3). Approximately 60% of the neoplastic cells of the RCC demonstrated moderate to strong cytoplasmic labeling for WSCK (Figure 3B), and ~80% of RCC neoplastic cells demonstrated strong cytoplasmic labeling for vimentin (Figure 3C). In the neoplasm from the accessory lung lobe, there was moderate to strong cytoplasmic labeling in >90% of the neoplastic cells for WSCK (Figure 3E) and the vimentin stain was negative for the neoplastic cells (Figure 3F). In the neoplasm from the right caudal lung lobe, there was diffuse strong cytoplasmic labeling of the neoplastic cells for WSCK (Figure 3H) and negative staining of the neoplastic cells with vimentin (Figure 3I).