Renal transitional-cell carcinoma in two cats with chronic kidney disease

Clinical outcomes in cats with renal carcinoma undergoing nephrectomy: A retrospective study

Renal carcinomas (RC) are uncommonly encountered in feline medicine. Limited information regarding clinical presentation and postoperative outcomes is available. The purpose of this multi-institutional, retrospective study was to describe the presenting features and clinical outcomes of cats with RC undergoing nephrectomy. Thirty-six client-owned cats were included. Medical records from participating institutions were searched to identify cats that had a histopathologic diagnosis of RC and underwent nephrectomy from January 2001 to October 2021. The most common presenting complaints were weight loss (36.1%) and hyporexia (30.6%). Based on preoperative imaging and intraoperative findings, eight cats had suspected metastasis at the time of surgery (22.2%). Twenty-eight cats survived to discharge (77.8%). Median progression free interval (PFI) could not be determined, as only six cats developed suspected recurrence (16.7%) and seven cats developed suspected metastasis (19.4%). The all-cause median survival time (MST) was 203 days (95% confidence interval [CI]: 84, 1379 days). When cases that died prior to discharge were excluded, MST increased to 1217 days (95% CI: 127, 1641 days). One-year, two-year, and three-year survival rates were all 40.4%. Neither renal tumour histologic subtype nor the presence of preoperative azotemia, anaemia, erythrocytosis, haematuria, or suspected metastasis at diagnosis were found to influence survival. For cats surviving to discharge, prolonged survival times were possible. Further studies are necessary to elucidate other potential prognostic factors, the utility of postoperative adjuvant treatment, and to identify cats at-risk of mortality in the perioperative period.

Renal Crest Proliferative Lesions in Cats with Chronic Kidney Disease

In a histopathological study of the renal crest (RC) of kidneys of cats with chronic kidney disease (CKD), 58/90 (64%) had epithelial proliferation. Of these, 33 cats had hyperplasia of the collecting duct (CD) epithelium (CDH) alone, eight had hyperplasia of the urothelium covering the RC (RCUH), of which one had concurrent abaxial renal pelvic urothelial hyperplasia (UH), and eight had both CDH and RCUH. CDH or RCUH were present in five cats with marked dysplasia of the CD epithelium (CDD) and four cats with invasive carcinomas, which also had epithelial dysplasia. All nine cats with marked dysplasia or neoplasia of the RC also had substantially altered RC contours due to focal haemorrhage, papillary necrosis or fibrosis. Three of the carcinomas had a strong desmoplastic response. In control cats, both urothelial (RC and renal pelvis) and tubular (CD and distal tubular) cells were immunopositive for cytokeratin (CK; AE1/AE3), tubular epithelial cells were positive for vimentin (Vim) and aquaporin 2 (Aq2), while urothelial cells were positive for p63. PAX8 immunolabelling was difficult to validate. CD and UH labelling was similar to control tissue. While urothelial dysplasia had the same immunolabelling pattern as UH and control tissue, CDD was generally immunonegative for Aq2. As immunolabelling of the four carcinomas did not distinguish between tubular and urothelial origin, with three positive for both Vim and p63, all were broadly designated as RC carcinomas. Overall, proliferative epithelial lesions are common in cats with CKD and form a continuum from simple hyperplasia to neoplasia of the urothelium or CD of the RC.

Renin-producing Tumour in the Kidney of a Cat

Clinical and post-mortem examination of an adult neutered male cat with immune-mediated haemolytic anaemia revealed suspected nodules of tumour tissue in the cortex of the right kidney. Cytology and histopathology indicated a malignant renal tumour of undetermined type. Immunohistochemistry confirmed renin production by a proportion of the tumour cells. The lesion may represent a renal adenocarcinoma producing renin or a tumour of juxtaglomerular cells ('reninoma').

Renal transitional cell carcinoma with bilateral ocular metastasis in a cat

Case summary A 4-year-old, spayed female, domestic shorthair cat was presented for evaluation due to a 4 day history of inappetence and lethargy. Physical examination revealed mild dehydration and blindness of the left eye. Abnormal imaging findings included a well-margined soft tissue mass with irregular central cavity located in the dorsal aspect of the caudal lung lobe. Cytological examination of the mass revealed chronic inflammation with hemorrhage. Tests for parasitic and fungal diseases were negative. Ophthalmic examination 17 days after the cat was initially presented revealed severe diffuse pathology of both retinas. Left renomegaly was noted 22 days after the initial presentation, and cytological examination of samples obtained from the right vitreous, left kidney and the pulmonary mass yielded atypical epithelial cells exhibiting malignant changes. Post-mortem examination following euthanasia revealed renal transitional cell carcinoma with metastasis to both eyes, lungs and skeletal muscle. Immunohistochemical evaluation of the neoplastic cells in the eye revealed moderate cytoplasmic reactivity for CK7. CK20 immunohistochemistry was negative.

Relevance and novel information To the best of our knowledge, this is the first report of renal transitional cell carcinoma with ocular metastasis in a cat. In addition, this report describes immunohistochemistry results of transitional cell carcinoma in a cat using CK7 and CK20.

Renal leiomyosarcoma in a cat

Renal leiomyosarcoma was diagnosed in a 10-year-old Domestic Shorthair cat with a 3-year history of clinically managed, chronic renal disease. Sudden death was preceded by a brief episode of mental dullness and confusion. At postmortem examination, the gross appearance of the left kidney was suggestive of hydronephrosis, and a nephrolith was present in the contralateral kidney. However, histology revealed an infiltrative, poorly differentiated, spindle cell sarcoma bordering the grossly cavitated area. Neoplastic cells were immunoreactive for vimentin and smooth muscle actin, which led to a diagnosis of renal leiomyosarcoma; neoplastic cells were not immunoreactive for desmin. Leiomyosarcoma arising in the kidney is a rare occurrence in humans and an even rarer occurrence in veterinary medicine with no prior cases being reported in cats in the English literature. The macroscopic appearance of the tumor at postmortem examination was misleadingly suggestive of hydronephrosis as a result of the large cavitation and may be similar to particularly unusual cases of renal leiomyosarcomas in humans that have a cystic or cavitated appearance.

Spontaneously arising concurrent ileocaecal adenocarcinoma and renal pelvis transitional cell carcinoma in a rhesus macaque (Macaca mulatta)

A 25-year-old, female rhesus macaque (Macaca mulatta) presented with a history of weight loss despite a normal appetite and supportive care. The animal was humanely destroyed due to poor prognosis. Post-mortem examination revealed a focally extensive, firm, white annular constriction at the ileocaecal junction and an incidental finding of a pale white nodule approximately 0.8 cm in diameter in the left renal pelvis. Based on the microscopical findings, ileocaecal adenocarcinoma and renal pelvis transitional cell carcinoma (TCC) were diagnosed. The use of cytokeratin (CK)-7 and -20 and uroplakin III as potential renal TCC markers was evaluated. The neoplastic cells were labelled intensely with antibodies to uroplakin III, but not to CK-7 or -20. Spontaneous intestinal adenocarcinoma has been documented in the rhesus macaque, but concurrent renal pelvis TCC is highly unusual.