Diagnosis of renal lymphoma by Wright-Giemsa-stained cytocentrifuged urine evaluation in a cat.

Lymphoma represents up to 30% of neoplasms diagnosed in cats. Diagnosis of lymphoma in the urinary system by examination of urine sediment has been described in a dog, but apparently not previously in cats. Concurrent samples of serum, EDTA whole blood, and urine were submitted from a 15-year-old spayed female domestic shorthair cat exhibiting weight loss, polyuria, and polydipsia. Hematology and biochemical abnormalities included a mild normocytic, normochromic, non-regenerative anemia; an inflammatory leukogram; and azotemia. Urinalysis evaluation revealed inadequate urine concentration and marked proteinuria. Wet-mount urine sediment examination revealed moderate numbers of leukocytes and erythrocytes. A uniform population of intermediate-to-large lymphocytes was observed on a fresh, Wright-Giemsa-stained preparation from cytocentrifuged urine. The cat was euthanized and necropsy was completed. Bilateral renomegaly was identified and characterized by multifocal, pale-yellow, coalescing, poorly defined, homogenous nodules. Microscopically, these nodules were composed of dense sheets of CD3-positive round cells, consistent with T-cell renal lymphoma. Key clinical message: Lymphoma is a common neoplasm in cats that can affect many organ systems, including the upper urinary tract. This case represents an uncommon method of identifying neoplastic lymphocytes via evaluation of cytocentrifuged urine, and emphasizes the benefits of examining Romanowsky-stained urine sediment in animals.

Diagnostic du lymphome rénal chez un chat par évaluation d'urine cytocentrifugée avec coloration Wright-Giemsa. Le lymphome représente jusqu'à 30 % des néoplasmes diagnostiqués chez le chat. Le diagnostic d'un lymphome du système urinaire par examen des sédiments urinaires a été décrit chez un chien, mais apparemment pas à ce jour chez le chat. Des échantillons simultanés de sérum, de sang total dans un tube avec EDTA et d'urine ont été soumis provenant d'une chatte domestique à poils courts stérilisée de 15 ans présentant une perte de poids, une polyurie et une polydipsie. Les anomalies hématologiques et biochimiques comprenaient une légère anémie normocytaire, normochrome et non régénérative; une formule leucocytaire inflammatoire; et une azotémie. L'analyse d'urine a révélé une concentration urinaire insuffisante et une protéinurie marquée. L'examen microscopique des sédiments urinaires a révélé un nombre modéré de leucocytes et d'érythrocytes. Une population uniforme de lymphocytes de taille intermédiaire à grande a été observée sur une préparation fraîche colorée au Wright-Giemsa à partir d'urine cytocentrifugée. Le chat a été euthanasié et une autopsie a été réalisée. Une rénomégalie bilatérale a été identifiée et caractérisée par des nodules multifocaux, jaune pâle, coalescents, mal définis et homogènes. Au microscope, ces nodules étaient composés de feuilles denses de cellules rondes CD3-positives, compatibles avec un lymphome rénal à cellules T.Message clinique clé :Le lymphome est une tumeur courante chez le chat qui peut affecter de nombreux systèmes organiques, y compris les voies urinaires supérieures. Ce cas représente une méthode rare d'identification des lymphocytes néoplasiques via l'évaluation de l'urine cytocentrifugée et met l'emphase sur les avantages de l'examen des sédiments urinaires avec coloration de Romanowsky chez les animaux.(Traduit par Dr Serge Messier).

Balloon catheter as an extraction device for caudal vena cava adrenal tumor thrombectomy in a dog: A case report.

OBJECTIVE: To report the use of a balloon catheter as an extraction device for a posthepatic caval thrombus in a dog with a right adrenal tumor. ANIMALS: Twelve-year-old male neutered Chihuahua mix dog. STUDY DESIGN: Case report METHODS: The dog presented for the evaluation of a hepatic mass. Computed tomography of thorax and abdomen was performed, and a right lateral liver lobe mass and a right adrenal mass were noted. The adrenal mass had a caval thrombus extending almost to the level of the right atrium. Traditional methods of tumor thrombectomy were unsuccessful. Extraction of the thrombus was facilitated by passing a balloon catheter through the caudal vena cavotomy until it was cranial to the thrombus, inflating the balloon and slowly withdrawing the catheter. RESULTS: A malignant pheochromocytoma was diagnosed on histology. The dog had a subjectively assessed good quality of life until it was euthanized 118 days postoperatively for acute dyspnea. CONCLUSION: Balloon catheter-assisted thrombectomy was successful in removing an extensive caval thrombus that was otherwise difficult to extract via conventional methods. This technique can be considered in cases with extensive tumor thrombus either as a method of choice or when other methods of thrombus extraction have failed.

Multi-modality imaging and therapeutics used in a case of canine spinal nephroblastoma.

A 4-year-old castrated male golden retriever dog was brought to a veterinary teaching hospital for evaluation of acute progressive paraparesis. Neurological examination indicated a spinal cord lesion between the third thoracic vertebra and third lumbar vertebrae. Magnetic resonance imaging (MRI) revealed an intradural, extra medullary, and/or intramedullary mass centered over the eleventh and twelfth thoracic disc space. The dog underwent cytoreductive surgery and histopathologic analysis diagnosed a nephroblastoma. Following this, the dog underwent multimodal therapy, including multiple surgeries, 2 courses of radiation, and combination chemotherapy. The dog had serial restaging using MRI, computed tomography (CT), and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography throughout the course of therapy. The dog survived 350 d from date of first presentation until humane euthanasia was elected due to worsening of neurologic status. During postmortem examination, extensive infiltration of the spinal cord by nephroblastoma cells was discovered as well as pulmonary metastatic disease. Key clinical message: Based on the literature search, this is the first case in which surgery, radiation therapy, and chemotherapy were all used for the treatment of canine spinal nephroblastoma. This case report details the aggressive nature of a case of canine spinal nephroblastoma despite multi-modal therapy.

Méthode d'imagerie et de thérapies multimodales utilisées dans un cas de néphroblastome spinal canin. Un chien golden retriever mâle castré âgé de 4 ans a été présenté dans un hôpital d'enseignement vétérinaire pour l'évaluation d'une paraparésie progressive aiguë. L'examen neurologique a révélé une lésion de la moelle épinière entre la troisième vertèbre thoracique et la troisième vertèbre lombaire. L'imagerie par résonance magnétique (MRI) a révélé une masse intradurale, extra-médullaire et/ou intramédullaire centrée sur les onzième et douzième espace de disque thoracique. Le chien a subi une chirurgie de cytoréduction et une analyse histopathologique a diagnostiqué un néphroblastome. Par la suite, le chien a subi une thérapie multimodale, comprenant plusieurs interventions chirurgicales, deux cycles de radiothérapie et une chimiothérapie combinée. Le chien a subi une reclassification en série par MRI, tomodensitométrie (CT) et tomographie par émission de positrons au fluor-18 fluorodésoxyglucose/tomodensitométrie tout au long du traitement. Le chien a survécu 350 jours à partir de la date de la première présentation jusqu'à ce que l'euthanasie soit choisie en raison de l'aggravation de l'état neurologique. Au cours de l'examen post-mortem, une infiltration étendue de la moelle épinière par des cellules de néphroblastome a été découverte ainsi qu'une maladie métastatique pulmonaire.Message clinique clé :D'après la recherche documentaire, il s'agit du premier cas dans lequel la chirurgie, la radiothérapie et la chimiothérapie ont toutes été utilisées pour le traitement du néphroblastome spinal canin. Ce rapport de cas détaille la nature agressive d'un cas de néphroblastome spinal canin malgré une thérapie multimodale.(Traduit par Dr Serge Messier).

A case of canine renal lymphoma of granular lymphocytes with severe polycythemia.

BACKGROUND: Renal lymphoma in dogs is rare and has a poor prognosis. Granular lymphocyte morphology is rarely reported in canine renal lymphoma. Mild to moderate polycythemia is reported in a number of canine renal lymphoma cases. CASE PRESENTATION: A 10-year-old Labrador retriever presented to a university veterinary teaching hospital after a 1-month history of polyuria, polydipsia, and pollakiuria and a 2-week history of abdominal distention, lethargy, and increased respiratory effort. Abdominal ultrasound showed a wedge-shaped to rounded, heterogeneously hypoechoic mass lesion in the left kidney. Cytologic analysis of a percutaneous aspirate of the mass was consistent with lymphoma of granular lymphocytes. Severe polycythemia (hematocrit 0.871) was noted on a complete blood cell count. Clonality analysis identified a clonally rearranged T-cell receptor (TCR) gene and immunohistochemical staining was CD3+, CD79a- and CD11d+, supporting cytotoxic T-cell lymphoma. CONCLUSIONS: To our knowledge, this is the first report of renal cytotoxic T-cell lymphoma with severe polycythemia in a dog. Severe polycythemia and renal cytotoxic T-cell lymphoma are both rare in dogs; this report adds to the body of knowledge on these conditions.

Polyostotic osteosarcoma associated with avian leukosis virus infection in a captive bare-faced curassow (Crax fasciolata).

BACKGROUND: Osteosarcoma is a malignant mesenchymal bone tumor. Although it is a common tumor in the appendicular skeleton of dogs and cats, it is rarely reported in birds. Retroviruses are usually associated with solid tumor development in different avian species. CASE PRESENTATION: This report aims to describe a case of osteosarcoma associated with the avian leukosis virus in a captive bare-faced curassow (Crax fasciolata). A captive adult female bare-faced curassow presented with lameness, hyporexia, and a non-ulcerative and firm tumor in the right femur. The bird was euthanized due to the poor prognosis. Histopathology revealed an infiltrative mesenchymal neoplasm consisting of spindle cells with moderate cell pleomorphism, organized in bundles and interspersed by marked deposition of the osteoid matrix, which was compatible with osteosarcoma affecting both femur and tibiotarsus, with renal metastasis. Immunohistochemistry of the primary and metastatic tumor demonstrated vimentin expression by neoplastic cells. Samples of the neoplasm, bone marrow, and spleen were processed for PCR, which enabled the demonstration of proviral avian leukosis virus (ALV) DNA. CONCLUSIONS: To the best of our knowledge, this is the first report of an osteosarcoma in a bare-faced curassow with an unusual polyostotic manifestation and associated with ALV infection.

Review of Histological Grading Systems in Veterinary Medicine.

Tumor grading is a method to quantify the putative clinical aggressiveness of a neoplasm based on specific histological features. A good grading system should be simple, easy to use, reproducible, and accurately segregate tumors into those with low versus high risk. The aim of this review is to summarize the histological and, when available, cytological grading systems applied in veterinary pathology, providing information regarding their prognostic impact, reproducibility, usefulness, and shortcomings. Most of the grading schemes used in veterinary medicine are developed for common tumor entities. Grading systems exist for soft tissue sarcoma, osteosarcoma, multilobular tumor of bone, mast cell tumor, lymphoma, mammary carcinoma, pulmonary carcinoma, urothelial carcinoma, renal cell carcinoma, prostatic carcinoma, and central nervous system tumors. The prognostic relevance of many grading schemes has been demonstrated, but for some tumor types the usefulness of grading remains controversial. Furthermore, validation studies are available only for a minority of the grading systems. Contrasting data on the prognostic power of some grading systems, lack of detailed instructions in the materials and methods in some studies, and lack of data on reproducibility and validation studies are discussed for the relevant grading systems. Awareness of the limitations of grading is necessary for pathologists and oncologists to use these systems appropriately and to drive initiatives for their improvement.

Outcomes after transperitoneal laparoscopic ureteronephrectomy for the treatment of primary renal neoplasia in seven dogs.

OBJECTIVE: To describe the perioperative characteristics and outcomes in dogs that underwent transperitoneal laparoscopic ureteronephrectomy (TLU) for primary renal neoplasia. STUDY DESIGN: Short case series. ANIMALS: Seven client-owned dogs. METHODS: Medical records were reviewed and data extracted regarding perioperative characteristics and animal outcomes. TLU was performed using a single-port + 1 or multiple port techniques. Hemostatic clips or a vessel-sealing device were used for occlusion of renal hilar vessels. The ureter was occluded and transected close to the ureterovesicular junction and the tumor was placed in a specimen retrieval bag for extraction from the abdomen. RESULTS: Preoperative contrast enhanced computed tomography (CECT) was performed in 6/7 dogs. Median estimated tumor volume measured from abdominal CECT removed by TLU was 32.42 cm3 (interquartile range [IQR] 14.76-94.85). Median surgery time for TLU was 90 minutes (IQR 85-105). In one dog, elective conversion to open laparotomy was performed due to large tumor size. Median time to discharge was 31 hours (IQR 24-48). No major perioperative complications occurred and all dogs survived to discharge. Progression free survival in four dogs was 422 days (IQR 119-784). CONCLUSION: TLU was performed for the extirpation of modest sized primary renal tumors with acceptable perioperative outcomes and a low complication rate. CLINICAL RELEVANCE: TLU may be considered for the treatment of selected cases of primary renal neoplasia in dogs.

Renal extramedullary plasmacytoma in a dog.

A 10-year-old, intact male Siberian husky dog was presented for a suspected left renal cyst. Computed tomography (CT) identified a large, left kidney mass with retroperitoneal hemorrhage. A left-sided nephrectomy was performed, and histopathology confirmed a renal plasmacytoma. Perioperative screening for multiple myeloma was negative. The dog was lost to follow-up and was euthanized 11 months after surgery. A necropsy was not performed. To the authors' knowledge, this is the first case of renal extramedullary plasmacytoma in a dog. Key clinical message: This report describes the clinical presentation, and laboratory, diagnostic imaging, and surgery findings of a case of renal extramedullary plasmacytoma in a dog.

Plasmocytome rénal extra-médullaire chez un chien. Un chien husky sibérien mâle intact de 10 ans a été présenté pour un kyste rénal gauche suspecté. La tomodensitométrie a identifié une grande masse rénale gauche avec une hémorragie rétropéritonéale. Une néphrectomie gauche a été réalisée et l'histopathologie a confirmé un plasmocytome rénal. Le dépistage péri-opératoire pour myélome multiple était négatif. Le chien n'a pas eu de suivi et a été euthanasié 11 mois après la chirurgie. Une autopsie n'a pas été réalisée. À la connaissance des auteurs, il s'agit du premier cas de plasmocytome rénal extra-médullaire chez un chien.Message clinique clé :Ce rapport décrit la présentation clinique et les résultats de laboratoire, d'imagerie diagnostique et de chirurgie d'un cas de plasmocytome rénal extra-médullaire chez un chien.(Traduit par Dr Serge Messier).

Myxosarcoma Associated with the Kidney in a Cat: Case Report.

A 12 yr old spayed female domestic shorthair with a history of lethargy, anorexia, and a pendulous abdomen was referred after a cranial abdominal mass was palpated on physical examination. Thoracic radiographs and an abdominal ultrasound revealed a mass associated with the kidney and moderate hemoperitoneum. Exploratory laparotomy revealed abdominal hemorrhage originating from a right renal mass that was adhered to the caudal vena cava. Following a right nephrectomy, histopathology diagnosed the mass as a perirenal/renal myxosarcoma. Based upon thoracic radiographs and abdominal ultrasound, the patient remains disease free at 14 mo postoperatively.

Single-Incision Laparoscopic Deroofing and Omentalization of a Cystic Renal Adenoma in a Dog.

A 12 yr old 13.5 kg male castrated Pembroke Welsh corgi was presented for evaluation of a suspected renal cyst following multiple episodes of lethargy and abdominal pain. Abdominal imaging revealed a large, thin-walled, hypoechoic cystic lesion associated with the cranial pole of the left kidney and a second smaller cystic lesion on the caudal pole. The larger cystic lesion was repeatedly drained percutaneously, but the lesion returned to initial size and clinical signs returned within weeks. Percutaneous ethanol sclerotherapy achieved only transient improvement in lesion size and abdominal discomfort. Laparoscopic deroofing and omentalization of the larger left renal cystic lesion was performed. The resected cystic wall was histopathologically consistent with a renal adenoma. Abdominal ultrasonography performed 1 mo postoperatively found no recurrence of the cystic renal adenoma. Repeated ultrasonography at 3 mo postoperatively detected a small cystic lesion at the cranial pole of the left kidney, which remained static in appearance at 11 and 18 mo postoperatively. During all follow-up visits, the dog was reported to be doing well with no recurrence of clinical signs. Renal cysts causing clinical signs and renal adenomas are rare in veterinary medicine; laparoscopic deroofing and omentalization provides a minimally invasive treatment approach.

RENAL NEOPLASIA FROM A SINGLE POPULATION OF PTEROPODID BATS.

Neoplastic diseases have rarely been reported in the family Pteropodidae, and primary malignant renal neoplasms are generally uncommon across animal species. This case series describes four cases of primary renal neoplasia: three renal cell carcinomas and one nephroblastoma in three species of pteropodid bats, specifically large flying foxes (Pteropus vampyrus, n = 2), straw-colored fruit bat (Eidolon helvum, n = 1), and a little golden-mantled flying fox (Pteropus pumilus, n = 1). Two of the cases were diagnosed antemortem using ultrasonography, computed tomography, and cytology; and one of these bats with a renal cell carcinoma was treated successfully with a unilateral nephrectomy. The remaining two cases were diagnosed at necropsy.

Perioperative morbidity and mortality in dogs with invasive adrenal neoplasms treated by adrenalectomy and cavotomy.

OBJECTIVE: To report the morbidity and mortality associated with adrenalectomy with cavotomy for resection of invasive adrenal neoplasms in dogs and evaluate risk factors for perioperative outcomes. STUDY DESIGN: Retrospective study. ANIMALS: Forty-five client-owned dogs. METHODS: Dogs that underwent open adrenalectomy with cavotomy for resection of adrenal masses with tumor thrombus extending into the vena cava were included. Clinicopathologic data were harvested from medical records. Selected clinical, imaging, and operative variables were statistically evaluated as risk factors for packed red blood cell transfusion, nephrectomy, perioperative death, and overall survival. RESULTS: Thirty-six of 45 masses were pheochromocytomas, 7 were adrenocortical carcinomas, and 2 were unknown type. Caval thrombus terminated prehepatically in 21 of 45 dogs and extended beyond the porta hepatis but terminated prediaphragmatically (intrahepatic prediaphragmatic location) in 15 dogs and thrombi extended postdiaphragmatically in 5 dogs. Thirty-four (76%) dogs were discharged from the hospital, and 11 (24%) dogs died or were euthanized prior to discharge. Median overall survival time for all 45 dogs was 547 days (95%CI 146-710). Bodyweight, tumor type, and size and extent of caval thrombus did not affect survival to discharge, but postdiaphragmatic (rather than prediaphragmatic) thrombus termination was associated with a greater risk of death. CONCLUSION: Long-term survival was common in dogs that survived the perioperative period. Postdiaphragmatic thrombus extension affected the prognosis for overall survival. CLINICAL SIGNIFICANCE: Findings of this study help to stratify operative risk in dogs with adrenal neoplasia and caval invasion.

Renal Nephroblastoma in a 17-Month-Old Jack Russell Terrier.

A 17 mo old female Jack Russell terrier was diagnosed with unilateral primary malignant nephroblastoma. The dog presented with polyuria and polydipsia. Laboratory tests revealed polycythemia and elevated serum erythropoietin levels. Diagnostic imaging (i.e., MRI) revealed a unilateral renal mass without spinal cord involvement. Nephrectomy was performed, and the histopathologic diagnosis was nephroblastoma. The dog did not receive any chemotherapy, and there was no evidence of recurrent disease or metastasis over 30 mo after nephrectomy. This is the first case report of a dog presenting with polyuria and polydipsia found to be a result of nephroblastoma. Furthermore, this is the longest survival reported for canine nephroblastoma treated with nephrectomy alone.

Histopathologic and Immunohistochemistry Findings in Feline Renal Cell Carcinoma.

The biological behavior and immunohistochemical features of feline renal cell carcinoma (RCC) have not been well characterized. In the present study, immunohistochemical examinations were performed in 12 feline cases of RCC. The RCC consisted of solid ( n = 2), solid-tubular ( n = 2), tubular ( n = 3), papillary ( n = 2), tubulopapillary ( n = 2), and sarcomatoid ( n = 1) type lesions. Of the cases with RCC, 1 developed metastatic disease and 6 cases had no evidence of recurrence at 80 to 2292 days after surgery. One papillary-type tumor had cuboidal cells with scant cytoplasm and monomorphic nuclei, and the other had pseudostratified columnar cells with abundant cytoplasm. Immunohistochemistry revealed that the tumor cells in most cases were positive for cytokeratin (CK)7, CK20, KIT, and CD10, with the exception of cases of the solid type with clear cytoplasm (solid anaplastic), papillary type with columnar cells, and sarcomatoid types. A small number of tumor cells in the solid anaplastic and in the sarcomatoid types were positive for aquaporin-1. Increased expression of N-cadherin and Twist along with nuclear accumulation of ß-catenin were observed in the sarcomatoid type. These results indicated that CK, KIT, and CD10 are relatively strongly expressed in most feline RCC. The solid anaplastic RCC exhibited CD10 expression with the absence of distal tubule marker expression. Although immunohistochemistry profiles were relatively consistent with those described in human RCC, the histopathologic features were different from those seen in humans. Epithelial-mesenchymal transition (EMT) marker expression in the current cases may suggest the involvement of an EMT-like mechanism in the development of sarcomatoid RCC in cats.

14-3-3σ Protein Expression in Canine Renal Cell Carcinomas.

14-3-3σ is a protein expressed in many epithelial tissues associated with essential cell functions, including cell-cycle control, apoptosis, and cytoskeletal integrity. There is a paucity of knowledge of the tumorigenesis of canine renal cell carcinomas (RCCs), and the histological origin of this tumor has not been established. This study analyzed the expression of 14-3-3σ, Ki-67, cytokeratins, and vimentin in 40 canine RCCs. Aberrant expression of 14-3-3σ was demonstrated in 15 (38%) cases and was associated with a significantly shorter survival time ( P < .002). In contrast to canine RCC, normal kidney did not express 14-3-3σ. The Ki-67 proliferation index did not show utility as a prognostic factor. The distal convoluted tubular epithelium in normal kidneys coexpressed cytokeratins and vimentin, and thus maintenance of this coexpression pattern in canine RCC suggests that most tumors arise from the distal segment of the nephron. These results suggest that 14-3-3σ is a potential negative prognostic factor and a possible therapeutic target.

Successful management of proteinuria and systemic hypertension in a dog with renal cell carcinoma with surgery, telmisartan, and amlodipine.

An 11-year-old neutered male Yorkshire terrier dog was presented with a 3-week history of hematuria and anorexia. A unilateral renal mass was detected and surgically removed. The renal mass was diagnosed on histopathologic examination as a renal carcinoma. Supportive medical therapy was carried out and persistent systemic hypertension was managed using telmisartan.

Gestion réussie de la protéinurie et de l'hypertension systémique chez un chien atteint d'un carcinome rénal à l'aide d'une chirurgie, de telmisartan et d'amlodipine. Un chien Yorkshire terrier mâle stérilisé âgé de 11 ans a été présenté avec une anamnèse de 3 semaines d'hématurie et d'anorexie. Une masse rénale unilatérale a été détectée et excisée par chirurgie. La masse rénale a été diagnostiquée à l'examen histopathologique comme étant un carcinome rénal. Une thérapie médicale de soutien a été réalisée et l'hypertension systémique persistante a été gérée à l'aide de telmisartan.(Traduit par Isabelle Vallières).

Pax8, Napsin A, and CD10 as Immunohistochemical Markers of Canine Renal Cell Carcinoma.

Pax8, napsin A, and CD10 are useful immunohistochemical markers of human renal cell carcinoma (RCC); however, their diagnostic utility in canine RCC is unclear. Forty formalin-fixed paraffin-embedded renal cell carcinomas from dogs (15 papillary, 12 solid, and 13 tubular) and 10 metastases were evaluated for expression of Pax8, napsin A, and CD10. Thirty-nine (98%), 24 (60%), and 19 (50%) tumors expressed Pax8 (nuclear labeling), napsin A (cytoplasmic labeling), and CD10 (cytoplasmic and membranous labeling), respectively. Pax8 was expressed in 92% of solid, 100% of papillary, and 100% of tubular tumors. Napsin A was expressed in 58% of solid, 60% of papillary, and 62% of tubular RCC. CD10 was expressed in 33% of solid, 47% of papillary, and 62% of tubular RCC. Pax8 was expressed in 80% of the metastatic tumors, napsin A in 60%, and CD10 in 50%. Additionally, Pax8 immunoreactivity was stronger overall than that of napsin A or CD10. In summary, Pax8 is a more sensitive marker than napsin A or CD10 for primary and metastatic canine RCC; its nuclear and more intense reactivity also makes it easier to interpret. Tubular and papillary RCCs were more likely than solid RCC to express all 3 markers. These findings highlight the utility of Pax8 as an immunohistochemical marker in diagnosing all major subtypes of canine primary and metastatic renal cell carcinoma.

Renal Cystic Adenocarcinoma in a Flowerhorn Cichlid with Metastatic Involvement of the Spleen.

A 480-g flowerhorn cichlid (an ornamental hybrid) with severe bilateral abdominal swelling, bulla-like structures on the skin, bilateral exophthalmia, and a prolapsed intestine was presented. Radiographs showed compression of the posterior part of the swim bladder and abdominal distention. Ultrasonography of visceral organs revealed a heterogeneous mass with hypoechoic to anechoic polycystic parenchyma and free fluid in the abdominal cavity. At necropsy, free fluid in the abdominal cavity and a large polycystic mass originating from the posterior kidney were observed. Histologically, the mass was composed of more cystic growth of tubules. The renal architecture was replaced by tubules, often irregular in shape, lined by simple to lightly stratified layers of neoplastic and pleomorphic cuboidal to columnar epithelial cells and the absence of glomeruli. Birefringent crystals were observed with polarized light within the lumen of some tubules. The apical border of the neoplastic cells was periodic acid-Schiff positive. Immunohistochemically, the neoplastic cells were positive for cytokeratin AE1/AE3 and proliferating cell nuclear antigen and were negative for p53 (tumor suppressor protein). Microscopic metastasis was seen in the spleen. The metastatic tumor was classified as a cystic adenocarcinoma of the kidney, originating from the proximal tubules. Received October 7, 2016; accepted June 18, 2017.

DIAGNOSIS AND TREATMENT OF A UNILATERAL RENAL CYSTADENOMA IN AN AFRICAN LION (PANTHERA LEO).

A renal tubular cystadenoma was diagnosed in a 14-yr-old male African lion (Panthera leo). During a routine health evaluation, a left renal mass was identified via physical examination, radiographs, and abdominal ultrasonography. The mass was 30 × 15 cm in size and had a thin capsule with central hypoechoic fluid, suggestive of a perirenal cyst. An exploratory celiotomy with partial nephrectomy was performed without complications. Histologically, the tumor was characterized by a thick fibrous capsule surrounding multiple, variable-sized cysts that markedly compressed the adjacent fibrotic and atrophied renal cortex. Immunohistochemical labeling for Aquaporin-1 and Tamm-Horsfall protein was consistent with a renal tubular cystadenoma of proximal tubule origin. Renal cystadenomas are an uncommon benign epithelial neoplasm. There are only two documented case reports in domestic cats. This report represents the first documentation, to the authors' knowledge, of a renal cystadenoma in a lion.

Renal Tumors in 26-Week Tg.Rash2 Mice Carcinogenicity Studies.

We report renal tubular adenomas and a carcinoma in 26-week Tg.rasH2 mouse carcinogenicity studies, which have not been reported to date either at our facility or in other published data. However, during the year 2014, renal tubular tumors were present in 4 studies conducted at our facility. Because of their morphological similarity to the amphophilic-vacuolar (AV) phenotypic variant of renal tubule tumors noted in Sprague-Dawley and Fischer 344 rats, which are thought to be familial, as well as the genetic homogeneity of Tg.rasH2 mice, we tracked the parents of these mice with tumors in each study. The origin of these tumors could not be traced back to any of the parents or even an animal barrier, and these tumors were not attributed to the vehicle or test article. Although the exact mechanism of tumorigenesis was not known, based on the available information, the development of renal tumors in these mice was considered random and spontaneous.