Radiographic characteristics of canine subungual keratoacanthoma.

Subungual keratoacanthoma (SKA) is a rare benign nail bed tumor in dogs, and its radiographic characteristics have not been reported based on the authors' review of the literature. The purpose of this multicenter, retrospective, observational, descriptive study was to describe the radiographic features of SKA in dogs. Twelve dogs for a total of 12 digits with histologically confirmed SKA met the inclusion criteria. The radiographs of the manus or pes were reviewed by two veterinary radiologists and one veterinarian. The radiology reports were interpreted based on a consensus. In six dogs, there was lysis of both the middle phalanx (P2) and the distal phalanx (P3), whereas in the other six dogs, there was only lysis of P3. In all dogs with osteolysis of P2, the lysis involved the distal articular surface. Osteolysis of P3 was more severe in the ungual process than in the ungual crest in all dogs. The margins of the lytic regions of P2 and P3 were well defined and smoothly marginated in most dogs. Expansile changes in the P3 crest were observed in 83.3% (10/12 dogs), and the nail of the affected digit was enlarged and deformed in 91.6% (11/12 dogs). In summary, the radiographic features of canine SKA include severe pressure resorption of the P3 ungual process, expansile change of the P3 ungual crest, and nail enlargement and deformation. With these radiographic features, SKA should be considered as a differential diagnosis.

Ultrasonographic Renal Subcapsular Thickening in Cats with Primary and Metastatic Carcinoma.

Ultrasonographic subcapsular thickening caused by renal neoplasia other than lymphoma has been previously reported in cats; however, detailed information is lacking. This study aims to describe ultrasonographic findings in renal subcapsular thickening and renal parenchyma in cats diagnosed or presumed with primary and metastatic carcinoma in the kidney. Ultrasound reports were retrospectively searched from 3 veterinary hospitals and 6 cats with 9 affected kidneys were included. Renal lesions were confirmed either cytologically or histopathologically as primary renal carcinoma with metastasis in the contralateral kidney (in 1 case), or metastatic pulmonary carcinoma (in 3 cases). Two patients were cytologically diagnosed with pulmonary carcinoma with concurrent renal subcapsular thickening. Eight kidneys affected by metastatic carcinomas showed relatively thin, focal, and homogeneously hypoechoic subcapsular thickening while a single kidney affected by primary renal carcinoma showed markedly thick, circumferential, and heterogeneously mixed iso- to hypoechoic lesion. The renal parenchyma, especially when just beneath the subcapsular lesion, exhibited at least one abnormality in all affected kidneys, most characterized by hyperechoic renal cortex with concurrent hypoechoic striations. This is the first report describing metastatic carcinoma causing renal ultrasonographic subcapsular thickening in cats. Our results suggest that renal carcinoma should be included in differential diagnoses when ultrasonographic subcapsular thickening is present in cats.

Improved detection of air-filled lesions using computed tomography in dogs with recurrent spontaneous pneumothorax through reduction of pulmonary atelectasis via positive pressure ventilation.

Introduction: Spontaneous pneumothorax in dogs is predominantly caused by the rupture of air-filled lesions, such as bullae or blebs. The efficacy of Computed Tomography (CT) in detecting these lesions has been deemed limited due to its reportedly low sensitivity. This retrospective, cross-sectional study investigates the utility of CT in eight dogs diagnosed with recurrent pneumothorax, all of which had surgical confirmation of the cause of the pneumothorax. Materials and methods: Thoracic radiographs were obtained before and the day following the CT studies. Initially, a CT study was conducted without positive pressure ventilation (pre-PPV CT). Subsequent CT studies were performed post-evacuation of pneumothorax and with positive pressure ventilation of 15 cmH2O until lung atelectasis was resolved (post-PPV CT). The pre-PPV CT and post-PPV CT images were anonymized and reviewed by two board-certified radiologists. The presence and morphology of air-filled lesions were evaluated on all images. Surgical findings were recorded and compared to the CT findings. Results: Air-filled lesions were detected in 5 out of 8 dogs in the pre-PPV CT studies and in all 8 dogs in the post-PPV CT studies. The CT findings of air-filled lesions were consistent with surgical findings. None of the dogs showed increased severity of pneumothorax in radiographs taken the day following the CT studies. Discussions: The study concludes that the resolution of lung atelectasis by evacuation of pneumothorax and positive pressure ventilation during CT studies is feasible and enhances the detection of air-filled lesions in dogs with recurrent spontaneous pneumothorax. This could potentially aid in improving surgical planning.

Prognosis of primary pulmonary adenocarcinoma after surgical resection in small-breed dogs: 52 cases (2005-2021).

BACKGROUND: Tumor size is an important prognostic factor in lung cancer in dogs, and the canine lung carcinoma stage classification (CLCSC) recently has been proposed to subdivide tumor sizes. It is unclear if the same classification scheme can be used for small-breed dogs. OBJECTIVES: To investigate whether the tumor size classification of CLCS is prognostic for survival and progression outcomes in small-breed dogs with surgically resected pulmonary adenocarcinomas (PACs). ANIMALS: Fifty-two client-owned small-breed dogs with PAC. METHODS: Single-center retrospective cohort study conducted between 2005 and 2021. Medical records of dogs weighing <15 kg with surgically resected lung masses histologically diagnosed as PAC were examined. RESULTS: The numbers of dogs with tumor size ≤3 cm, >3 cm to ≤5 cm, >5 cm to ≤7 cm, or >7 cm were 15, 18, 14, and 5, respectively. The median progression-free interval (PFI) and overall survival time (OST) were 754 and 716 days, respectively. In univariable analysis, clinical signs, lymph node metastasis, margin, and histologic grade were associated with PFI, and age, clinical signs, margin, and lymph node metastasis were associated with OST. Tumor size classification of CLCS was associated with PFI in all categories, and tumor size >7 cm was associated with OST. In multivariable analysis, tumor size >5 cm to ≤7 cm and margin were associated with PFI, and age was associated with OST. CONCLUSIONS AND CLINICAL IMPORTANCE: The tumor size classification of CLCS would be an important prognostic factor in small-breed dogs with surgically resected PACs.

Clinical features and prognosis of retroperitoneal hemangiosarcoma in dogs with surgical resection with or without adjuvant doxorubicin.

Retroperitoneal hemangiosarcoma (RPHSA) is a rare tumor in dogs with a poorly understood prognosis after surgery. The objectives of this study were to investigate the clinical features and prognosis of canine RPHSA that had undergone surgical resection. In this single-center, retrospective cohort study, we reviewed the medical records of dogs that had undergone surgical resection for retroperitoneal tumors and received a histopathologic diagnosis of HSA between 2005 and 2021. The median progression-free survival (PFS) and overall survival (OS) were 77.5 days and 168 days, respectively. In the present study, canine RPHSA had an aggressive biological behavior similar to visceral HSA. Further studies in larger canine populations are needed to evaluate the efficacy of adjuvant chemotherapy.

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat.

An 11-year-old neutered male Domestic Shorthair cat presented with a 3-month history of hypoglycemia, two episodes of seizure, and intermittent tick-like signs. Serum biochemistry revealed severe hypoglycemia associated with high insulin concentrations. Dynamic abdominal computed tomography (CT) indicated two pancreatic masses, which were enhanced most during the late arterial phase but had different degrees and variations of attenuation. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed that one mass was an insulinoma and the other was an ectopic splenic tissue, consistent with the differences in imaging findings. When an intrapancreatic lesion with hyper-attenuation on dynamic abdominal CT is detected, not only insulinoma or metastasis of malignancies but also intrapancreatic accessory spleen (IPAS) should be considered as differential diagnoses.

Long-term survival in a dog with primary hepatic neuroendocrine tumor treated with toceranib phosphate.

Primary hepatic neuroendocrine tumors (PHNETs) are rare in dogs, and limited information exists about the treatment of these tumors. A 12-year-old castrated male French bulldog was presented to our clinic with gastrointestinal signs. Diagnostic tests revealed increased hepatic enzyme levels, a mass in the hepatic quadrate lobe, multiple intrahepatic nodules, and enlarged hepatic hilar lymph nodes. The liver mass was diagnosed cytologically as a malignant epithelial tumor suspected to be of neuroendocrine origin. The dog was treated with single-agent toceranib phosphate (TOC) and survived 25.1 months after the initial presentation. On necropsy, a liver mass was found and was subsequently diagnosed as a PHNET on histopathology. To the best of our knowledge, this is the first report of long-term survival in a dog with PHNET treated with TOC.