Canine extraskeletal osteosarcoma and chondrosarcoma: a clinicopathologic study of 14 cases

Canine extraskeletal osteosarcomas are extremely rare tumors. Over a period of 25 years at the Animal Medical Center, approximately 1,000 cases of skeletal osteosarcomas have been diagnosed. During the same period 11 cases of extraskeletal osteosarcomas and three extraskeletal chondrosarcomas were diagnosed. Tumors of the mammary gland were excluded. Extraskeletal osteosarcomas were found in the adrenal gland, eye, gastric ligament, ileum, kidney, liver, spleen, testicle, and vagina. The chondrosarcomas were found in the mitral valves, lungs, and omentum. The mean age of the dogs with extraskeletal osteosarcoma was 11 years, and the mean age of the dogs with extraskeletal chondrosarcoma was 14 years. The The sizes of the tumors ranged from 3 cubic centimeters to 8,315 cubic centimeters. Osteoblastic osteosarcomas were the most common histologic type (7/11, 63.6%); there was a single case of each of the following: fibroblastic, fibrous histiocytic, chondroblastic, and mixed osteo-chondroblastic osteosarcoma. Two of the dogs with chondrosarcomas had mesenchymal chondrosarcomas involving the lungs and omentum. The remaining dog had a regular chondrosarcoma involving the mitral valve. Distant metastases were present in seven of 11 dogs with extraskeletal osteosarcoma and in none of the dogs with chondrosarcoma. In contrast to human beings, in which most extraskeletal osteosarcomas occur in the soft tissues and the extremities, most canine extraskeletal osteosarcomas develop in the visceral organs.     

Feline urate urolithiasis: a retrospective study of 159 cases

The objective of the study was to characterize the signalment, clinicopathologic data, and diagnostic imaging of cats with urate urolithiasis, as well as the salts of uric acid present in the uroliths. A retrospective analysis of feline urate uroliths submitted to the GV Ling Urinary Stone Analysis Laboratory between 2000 and 2008 was included. From these data, records were assimilated from referring veterinarians (143); furthermore, all recorded cases from within the William R Pritchard Veterinary Medical Teaching Hospital (16) were included. Median values for the complete blood count and chemistry panels available were within the reference intervals, when provided, with only a few outliers present. Of all cases evaluated, seven had a portosystemic shunt (PSS). Cats with urate uroliths and a PSS were younger than cats without a PSS (2 years vs 7 years). The pathogenesis of urate uroliths in cats is poorly understood. Most cats were not completely evaluated for a PSS, however, clinicopathologic parameters indicating hepatic dysfunction were seldom noted; more sensitive diagnostics such as serum bile acids were rarely performed to confirm or negate the presence of a shunt. Studies are warranted to evaluate pathogenesis of urate uroliths to tailor proper management and breeding strategies.     

Soft tissue sarcomas in the African hedgehog (Atelerix albiventris): microscopic and immunohistologic study of three cases.

Three soft tissue tumors from 2 female hedgehogs were examined microscopically and immunohistochemically. Two tumors involved haired skin and the third one was vaginal. Microscopically, the cutaneous tumors had features of malignant peripheral nerve sheath tumor (MPNST), whereas the vaginal tumor was classified only as a spindle cell sarcoma. Immunohistochemically, all 3 tumors were strongly positive for vimentin and strongly to moderately positive for CD10 and neuron-specific enolase but did not stain with antibody to S100 protein, an antigen typically present in human MPNST The cutaneous tumor from hedgehog no. 1 was examined ultrastructurally and the neoplastic cells resembled fibroblasts. Hedgehog no. 1 was euthanized at the time of the biopsy. The outcome of the other hedgehog was unknown.     

Feline pyothorax: a retrospective study of 27 cases in Australia

Pyothorax was diagnosed in 27 cats between 1983 and 2002. In 21 (78%) of the cases, pleural fluid culture and/or cytology was consistent with a mixed anaerobic bacterial infection of oropharyngeal origin. In six cases (22%), infection was caused by unusual pathogens or pathogens of non-oropharyngeal origin, including a Mycoplasma species, Cryptococcus gattii, Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. The overall mortality rate was 22%. Treatment was successful in 18 of 19 cases (95%) where closed thoracostomy tubes were inserted. One case resolved only after thoracotomy. Actinomyces species were isolated in three cases and in contrast to dogs where thoracotomy is recommended, they were resolved with tube thoracostomy. Mechanical complications occurred in 58% of the cats with indwelling chest tubes. Probable mechanisms of pleural space infection were identified in 18 cats (67%) including haematogenous infection (n=1), direct inoculation of bacteria into the pleural space (n=1), intrathoracic oesophageal rupture (n=1) and parapneumonic extension of infection (n=15; 56%). Of the latter, perioperative aspiration was suspected in two cats, parasitic migration in two and antecedent upper respiratory tract infection was implicated in seven. Parapneumonic spread of infection after colonisation and invasion of lung tissue by oropharyngeal flora appears to be the most frequent cause of feline anaerobic polymicrobial pyothorax and contests the widespread belief that direct inoculation of pleural cavity by bite wounds is more common.     

The clinicopathologic, light, and scanning electron microscopic features of eperythrozoonosis in four naturally infected llamas

The hematologic, biochemical, and light and scanning electron microscopic features of eperythrozoonosis in four llamas are described. One female and three male yearling llamas were presented for evaluation of chronic weight loss. Three of four llamas had historical evidence of chronic inflammatory conditions. On examination, multiple clinical problems were apparent, including poorly to non-regenerative anemia, inflammatory disease, and hypoproteinemia. Coccoid- and ring-shaped basophilic organisms were present on the erythrocytes of all the llamas. On scanning electron microscopy, individual, pairs, and clusters of coccoid-shaped organisms were present on the erythrocytes. The organisms measured 0.4 to 0.6 micron in diameter and caused no marked deformation of the erythrocyte membrane. A rare organism could be found that produced a slight indentation into the erythrocyte membrane. The light and scanning electron microscopic morphologic features suggested that the organism was an Eperythrozoon. Serial evaluation of serum iron concentrations of the llamas showed a decrease serum iron in all animals, with a concurrent decrease in the total iron binding capacity and percent transferrin saturation in two of the llamas. Common abnormalities seen on serum electrophoresis included a decrease in albumin and beta serum fraction in all llamas and a decrease in the gamma globulin fraction of two individuals.     

Hepatobiliary neuroendocrine carcinoma in cats: a clinicopathologic, immunohistochemical, and ultrastructural study of 17 cases

Hepatobiliary neuroendocrine carcinoma was diagnosed in 17 cats in a period of 10 years. Seven tumors were of intrahepatic origin, one of which was a composite containing components of epithelial and neuroendocrine carcinoma. Nine tumors were of extrahepatic origin, and one tumor was located in the gall-bladder. The cats were adult and geriatric, and the male : female ratio varied according to tumor group. Hepatomegaly, anorexia, weight loss, and vomiting were the most common clinical signs observed in the cats with hepatic neuroendocrine carcinoma. The cats with extrahepatic neuroendocrine carcinoma showed these signs plus icterus (5/9) and high concentrations of hepatic enzymes. Histologically, the hepatic neuroendocrine carcinomas had two patterns, one with acinar structures separated by vascular stroma lined by cuboidal or columnar cells and the other solid with groups of anaplastic cells separated by vascular stroma. The composite tumor consisted of both bile duct carcinoma and neuroendocrine carcinoma. The extrahepatic neuroendocrine carcinomas and the gallbladder neuroendocrine carcinoma were characterized by solid sheets or groups of round to oval cells with vascular or fibrovascular stroma. Immunohistochemical examination of 10 of the neuroendocrine carcinomas revealed that all 10 stained with neuron-specific enolase; one bile duct carcinoma and the gallbladder carcinoma stained with chromogranin; four of five bile duct carcinomas and the gall bladder carcinoma stained with synaptophysin; and one bile duct carcinoma stained with gastrin. One cat with hepatic carcinoma had duodenal ulcer; in this cat, ultrastructural studies showed neurosecretory granules leading to the diagnosis of Zollinger-Ellison syndrome. In four cats in which necropsy was permitted, carcinomatosis (4/4), lymph nodes (4/4), lungs (2/4), and intestines (1/4) were the metastatic sites. Fourteen of the 17 cats were euthanatized during or immediately after surgery.     

FC-23 Feline plasma cell pododermatitis: a retrospective study of 26 cases

The objective of this open pilot study was to evaluate the efficacy of topical tacrolimus ointment for treatment of plantar fistulae in German shepherd dogs. Seven dogs (four males, three females) were included. All subjects had a 6-month to 2-year history of plantar fistulae involving the plantar aspect of two to four metatarsi/metacarpi. No other skin lesions were present and the dogs appeared otherwise healthy. Before treatment with tacrolimus, all dogs received antibiotics for 4–8 weeks. Hair was clipped to visualise the lesions. The presence of erythematous papules, oedema and fistulae was recorded for each foot. All dogs served as their own controls. Dogs with four legs involved had one front and one hind leg treated. Dogs with two to three feet affected had only one foot treated. Tacrolimus 0.1% ointment (Protopic^®) was applied twice daily onto the site of lesions. Partial improvement of treated lesions was seen in all cases within 3 weeks. After 6 weeks, treated lesions were in complete remission in four dogs, while the other three subjects had palpable but invisible lesions. Signs had not improved on the untreated legs. Follow-up varied between 4 months and 2 years. Lesion remission persisted in six dogs with the intermittent application of tacrolimus. Adverse effects of treatment were not seen. In conclusion, the application of topical tacrolimus seems to provide a safe and effective treatment option for plantar fistulae in German shepherd dogs.
Funding: Self-funded.     

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.     

Paranasal meningioma in the dog: a clinicopathologic study of ten cases

Paranasal meningiomas were diagnosed in ten dogs based on gross and light microscopic examinations of tissue specimens, and, in one case, electron microscopic examination. Seven of ten dogs were female (average age was 13 years). Most dogs (7/10) had seizures on examination. Two dogs with meningioma located in the nasal cavity had nasal discharge, and one had epistaxis. Tumors originated in the nasoparanasal region (eight) and frontal region of the cranial cavity (two). The histologic types of meningioma included psammomatous (two), transitional (three), meningotheliomatous (two), fibroblastic (two), and angioblastic (one). Tumors were malignant and extended to the brain in eight cases. These tumors differed from intracranial meningiomas mainly in their more anaplastic nature and aggressive behavior.     

Chicken anemia agent: an electron microscopic study

Particles of chicken anemia agent (CAA) negatively stained with uranyl acetate were found to be 26.5 nm in diameter. The surface detail evident on the particles indicated that the virus capsid was composed of 32 structural subunits arranged as in a class P = 3 icosahedron with a triangulation number of 3. Using mouse monoclonal antibodies to CAA and a gold-labeled goat anti-mouse IgG, CAA-specific structures were observed by thin-section electron microscopy in infected MDCC-MSB1 cells and in thymic lymphocytes from experimentally infected chicks. These consisted of electron-dense, granular, non-membrane-bound nuclear inclusions, which were often ring-shaped, and cytoplasmic accumulations of microtubules. Aggregates of virus-like particles were sometimes observed in the nuclei of infected MDCC-MSB1 cells. The nucleolar involvement that is characteristic of the morphogenesis of parvoviruses was not observed with CAA.     

Feline cutaneous fibropapillomas: clinicopathologic findings and association with papillomavirus infection

Twenty-three feline cutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by dermal fibroblastic proliferation with overlying, often ulcerated hyperplastic epidermis. Electron microscopic findings supported the fibroblastic nature of the neoplastic cells. The 23 tumors came from 20 cats and were submitted from veterinary clinics in Wisconsin and Minnesota. These tumors occurred most commonly in young cats and were found primarily on the head, neck, and digits. Fifteen of the 17 cats for which breed was reported were domestic shorthair cats. In 11/20 cases, there was confirmed exposure to cattle. Local recurrence of the tumor following surgical excision was reported in 7 of the 18 cats for which follow-up information was available. Metastasis was not documented in any of the cases. Two of the 19 tumors tested by polymerase chain reaction (PCR) had no amplifiable DNA. The remaining 17 were positive for papillomavirus by PCR. No papillomavirus DNA was detected in three other feline skin tumors (cutaneous mast cell tumor, malignant lymphoma, and fibrosarcoma) that served as controls. This is the first report of detection of papillomavirus in feline tumors that have clinicopathologic features similar to equine sarcoids.     

Feline histoplasmosis: a retrospective study of 22 cases (1986-2009)

Twenty-two cases of feline histoplasmosis seen at the Virginia-Maryland Regional College of Veterinary Medicine Teaching Hospital between 1986 and 2009 were reviewed. The median age of affected cats was 9 yr (mean, 8.8 yr). Female domestic shorthairs were more commonly affected. The clinical presentation of most cases was nonspecific. The most common presenting complaints included weakness, lymphadenopathy, weight loss, and anorexia. Less frequent clinical signs included vomiting, diarrhea, blindness, and lameness. Less than half of the cats had clinical evidence of pulmonary disease on admission. Anemia and hypoalbuminemia were common laboratory abnormalities. An interstitial pattern was the most common radiographic pattern observed with pulmonary disease. Diagnosis was based on identification of the organism on cytology or histopathology. Fifteen of the 22 cats were treated, and itraconazole was the most common antifungal agent prescribed. Median duration of the antifungal treatment was 5 mo for cats that survived to discharge. Overall survival at time of discharge for cats in this study was 55%.     

Feline necrotising sialometaplasia: a report of two cases

Unilateral swelling of submandibular salivary gland in two cats was diagnosed as necrotising sialometaplasia. Histological features that differentiate the disease from other salivary gland lesions, particularly neoplasia are: lobular necrosis of salivary tissue; squamous metaplasia conforming to duct and/or acinar outlines; preservation of salivary lobular morphology; and variable inflammation and granulation tissue.     

Colorectal polyps of the dog: a clinicopathologic study of 17 cases.

Seventeen cases of colorectal polyps in the dog were seen at the Ontario Veterinary College over a 12-year period. The mean age of occurrence was 6.9 years, and males and females were almost equally affected. The Collie was the most frequently affected breed (4/17). The clinical signs were typically dyschezia, periodic intermittent diarrhea and melena, and rectal prolapse of the polyp. The histopatholic classifcation were hyperplastic polyp (1), papillary adenoma (1), tubular adenoma (4), papillotubular adenoma (10), and unclassified (1). Severe epithelial atypia, likely carcinoma in situ, was apparent in 5 of the papillotubular adenomas. Retrospective analysis of survival data after polypectomy suggested a good prognosis, but the results were inconclusive and it is possible that some of the polyps represented premalignant lesions. Large polyps (greater than 1 cm in diameter) frequently had marked epithelial atypia and were considered more likely to recur or to become malignant.     

Feline superficial pyoderma: a retrospective study of 52 cases (2001-2011)

Background – Superficial pyoderma is traditionally considered rare in cats but may be more prevalent than previously reported. Objectives – To better characterize superficial pyoderma in cats. Animals – Fifty‐two cats from a dermatology referral population over a 10 year period. Methods – This study was retrospective. Cases were included if neutrophils and intracellular bacteria were reported from surface cytology of skin lesions. Medical records were reviewed for signalment, historical and clinical data, cytology results, primary skin diagnoses and treatment details. Results – Disease prevalence was 20%, with no breed or sex predispositions. The estimated median age of onset was 2 years, affecting 54% of cats by 3 years and 23% after 9 years. Fewer cases presented during winter (15%) compared with other seasons. Skin lesions were typically multifocal, affecting the face (62%), neck (37%), limbs (33%) and ventral abdomen (29%) most commonly. Crusting (83%), alopecia (67%), ulceration/erosion (54%) and erythema (46%) were common lesion types. Pruritus was reported in 92% of cats. Underlying hypersensitivities (confirmed in 60%; suspected in 19%), and atopic dermatitis specifically (confirmed in 48%), were the most frequent primary dermatoses. Cats were treated with a variety of systemic and/or topical antimicrobials. The overall apparent response was considered good in 61% and poor in 27% of cats. Recurrence was confirmed or suspected in 42% of cats. Conclusions and clinical importance – Feline superficial pyoderma was more prevalent in this study population than previously reported. Young cats with hypersensitivities and older cats were more commonly affected, and a variety of lesion types and distributions occurred.     

Experimental hamster enteritis: an electron microscopic study.

Hamster enteritis (HE) was experimentally produced in weanling hamsters by orally inoculating healthy hamsters with suspensions of ilea obtained from hamsters with HE. Control groups of hamsters were inoculated orally with suspensions of ilea from healthy hamsters. Electron microscopy was done on ilea from 6 control hamsters, 31 hamsters with experimentally produced HE, and 4 hamsters with naturally occurring HE. Ultrastructural changes were not observed in the absorptive epithelium of control animals. Two different intracytoplasmic bacterial organisms were observed in epithelial cells of hamsters with experimentally produced HE. Organisms that were observed early in the disease process were identified as Escherichia coli. Organisms ultrastructurally similar to Campylobacter spp were observed later in the disease and were only within hyperplastic epithelial cells. The hyperplastic ileal epithelium of hamsters with naturally occurring HE contained campylobacter-like organisms.     

Feline cutaneous hemangiosarcoma: a retrospective study of 18 cases (1998-2003)

Cutaneous hemangiosarcoma (HSA) has been infrequently reported in dogs and cats. Medical records of 18 cats diagnosed with cutaneous HSA were reviewed. Age at the time of diagnosis, breed, sex, tumor location, tumor size, treatment type, survival time, disease-free interval, and cause of death were evaluated. Aggressive surgical excision of the tumor was attempted in 10 cats. A complete surgical excision was achieved in five of the 10 cats. Median survival times were statistically longer in cats that underwent surgery versus cats that did not. Cats with cutaneous HSA treated with aggressive surgical excision of their tumors may have a good long-term prognosis.