Camelid mucoutaneous fibropapillomas: clinicopathologic findings and association with papillomavirus

Five camelid mucocutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by a dermal fibroblastic proliferation and overlying, often ulcerated hyperplastic epidermis with thin rete pegs extending down into the dermis. Two of the tumors came from llamas and three from alpacas. Four of the animals were 6-year-old females. The fifth was a 6-year-old castrated male. The fibropapillomas were located on the nose, lip, and cheeks. One of the llama tumors waxed and waned before surgery and recurred and spread after surgery. None of the other tumors recurred. All five tumors were positive for papillomavirus (PV) DNA by polymerase chain reaction testing. Nucleotide sequence analysis of the PCR product from one of the llama fibropapillomas confirmed a unique PV. This report provides the microscopic and clinical features of fibropapillomas in camelids as well as evidence for a PV etiology.     

Feline papillomavirus infection in a cat with Bowen-like disease and cutaneous squamous cell carcinoma

A cutaneous mass in the neck was excised in a 13-year-old cat. Histopathological examination of the resected tissue revealed a multicentric squamous cell carcinoma in situ resembling Bowen's disease of man. The tumor showed a multifocal transformation to an infiltrative squamous cell carcinoma. Histological and immunohistological findings excluded actinic keratosis and feline viral plaques and allowed a classification as an irregular non-hyperkeratotic type of multicentric squamous cell carcinoma in situ. As a possible causative agent feline papillomavirus type 2 was detected using nested PCR in formalin-fixed material.     

Feline cutaneous viral papilloma associated with human papillomavirus type 9

A 12-year-old domestic Shorthaired cat developed a multinodular exophytic mass on the dorsal surface of the nose. The skin surrounding the mass was nonpigmented, and actinic keratosis had been diagnosed in this area 3 years previously. Histologic examination revealed hyperkeratosis, epidermal hyperplasia, papillomatosis, koilocytosis, and possible intranuclear viral inclusions. Polymerase chain reaction amplified papillomaviral deoxyribonucleic acid from formalin-fixed samples of the lesion. Sequencing of the amplicon revealed 98% similarity to human papillomavirus (HPV) type 9. To the authors' knowledge, this is only the second reported feline cutaneous viral papilloma. In addition, this is the first report of a feline papilloma being associated with an HPV.     

Expression of connexin 26 and bovine papillomavirus E5 in cutaneous fibropapillomas of cattle

Bovine papillomaviruses (BPVs) can infect epithelial cells and fibroblasts, inducing fibropapillomas in cattle. Gap junctions are communication channels between cells composed of connexins (Cxs). This study evaluated expression of Cx26 and the major BPV oncoprotein E5 in bovine cutaneous fibropapillomas. BPV DNA was amplified from 20/20 fibropapillomas and 3/3 samples of normal skin. All fibropapillomas (20/20) were positive by immunostaining for E5, whereas the three normal skin samples were negative. Cx26 was expressed faintly in the normal skin epithelium. Positive cytoplasmic and juxtanuclear immunoreactivity for Cx26 was evident in 18/20 (90%) fibropapillomas. Western blot analysis demonstrated higher expression of Cx26 in 6/6 fibropapillomas compared to normal skin samples.     

Feline hyper-eosinophilia with cutaneous lesions

Feline hypereosinophilic syndrome was first reported by Hendrick (1981) and in four subsequent communications a further six cases have been described (McEwan and others 1985, Tobias 1985, Scott and others 1985, Verhaert and others 1987). With the exception of one report (Scott and others 1985) which described a case with cutaneous lesions, cats have exhibited clinical signs related to internal lesions. This communication describes a case of feline hypere-osinophilia with cutaneous lesions which proved refractory to treatment.     

Feline cutaneous neuroendocrine carcinoma (Merkel cell tumour): clinical and pathological findings

A case of a feline Merkel cell tumour is described. An 8-year-old, female cat developed a round, alopecic, reddish mass on the nose. Wide excisional surgery was performed with cartilage resection. Histologically the mass was composed of solid islands of mostly basophilic densely packed cells with a scant cytoplasm, which was suggestive of a neuroendocrine origin. Results of immunohistochemical studies using antibodies against neurone-specific enolase, chromogranin, synaptophysin and pan-cytokeratin allowed classification of the lesion as a Merkel cell tumour. Ultrastructurally, dense core granules were identified in the cytoplasm. In a 2-year follow-up no relapses or metastases were observed. The clinical course recorded is in contrast with the malignant nature of a Merkel cell tumour recently described in a cat and of the human Merkel cell tumour, but is similar to the course of the canine Merkel cell tumour which is often benign. Early diagnosis along with the use of wide surgical excision might be considered an important factor in preventing relapse of this tumour.     

Unusual metastatic behavior and clinicopathologic findings in eight cats with cutaneous or visceral hemangiosarcoma

Eight cats with visceral or cutaneous hemangiosarcoma were evaluated, and unusual metastatic and clinicopathologic behavior was evident in each. Cutaneous hemangiosarcoma is generally believed to be locally aggressive and slow to metastasize. These 8 cats with cutaneous hemangiosarcoma, however, developed metastatic disease after initial surgical resection; only 1 had local regrowth of the tumor. All cats with visceral hemangiosarcoma had metastasis at the time of diagnosis, which is consistent with cats of other reports. Three of 8 cats had evidence of disseminated intravascular coagulation, including increased prothrombin time and partial thromboplastin time, decreased number of platelets, and anemia. These potential complications need to be considered when planning diagnostic and treatment protocols.     

Congenital cutaneous fibropapillomatosis with no evidence of papillomavirus infection in a piglet

Multiple yellowish-white, cauliflower-like mass lesions on the skin of the head and back in a 4-month-old piglet were pathologically examined. These lesions had developed before the weaning period. Histologically, the cutaneous neoplasms were characterized by papillary outgrowth of connective tissue covered by thick epidermis. Hyperplasia of the epidermis was corresponded with proliferation of capillaries, lympho-plasmacytic infiltration, and proliferation of fibroblasts in the dermal stroma. There were no inclusion bodies and significant degeneration in the keratinocytes. Papillomavirus antigen and DNA were not detected in these lesions by immunohistochemistry and polymerase chain reaction, respectively. Accordingly, the fibropapillomatosis of the present case might be hamartomatous rather than infectious.     

Feline cutaneous toxoplasmosis: a case report

A 9-year-old female, domestic short hair cat was presented with sudden onset of polyuria/polydipsia, and hundreds of cutaneous nodules. Prior to referral, the cat had had four skin nodules that were treated with steroids. The four skin nodules then multiplied to form more than 100 ulcerated and nonulcerated nodules located all over the trunk. Clinical evaluation revealed hypothermia and respiratory distress. Cytology from both skin nodules and bronchoalveolar lavage showed macrophages and small organisms whose shape and size were indicative of Toxoplasma spp., or similar organisms. Feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) serology results were negative. The cat was seropositive for Toxoplasma (IgG 1 : 640) and Neospora (1 : 80) infections. The cat died soon after referral. Necropsy revealed pyothorax, necrotic/purulent pneumonia, haemorrhagic spots on kidneys and mesentery. Histopathology from skin nodules showed diffuse, deep necrotic dermatitis/panniculitis, vasculitis and disseminated free and grouped protozoa. The parasites were found in lungs, spleen, kidneys and liver. Immunohistochemistry on skin tissue with anti-Toxoplasma gondii and Neospora caninum antibodies gave positive results with both. Electron microscopy showed single and grouped tachyzoites with morphological features of T. gondii, often within macrophages. Samples of cutaneous nodules and bronchoalveolar fluid were examined by a polymerase chain reaction (PCR) assay for detecting apicomplexa coccidia. PCR results were consistent only with T. gondii infection. Therefore, immunohistochemistry positivity for N. caninum was considered a cross-reaction and a diagnosis of cutaneous and visceral toxoplasmosis was made.     

Feline cutaneous and visceral necrotizing panniculitis and steatitis associated with a pancreatic tumour

The association of pancreatic disorders with fat necrosis in domestic animals is rare. This report concerns a case of cutaneous/subcutaneous necrotizing panniculitis and steatitis associated with a pancreatic adenocarcinoma in an 11-year-old male Siamese cat. Clinical investigation revealed variably sized nodules on the trunk, limbs and abdomen. Some of them were ulcerated; others showed a shiny yellow necrotic background featuring irregular sinus tracts. The cat was euthanized at the owner's request before a diagnosis could be made. At necropsy, abundant oily material resembling mustard replaced the subcutaneous tissue and small yellow nodules were disseminated in the omentum, mesentery and serosa of the abdomen. A multilobulated mass arising from the anterior pancreatic head was found along with liver and lymph node metastasis. Histopathology showed wide fistulous tracts draining necrotic fat from the subcutis toward the surface and multifocal areas of necrotic adipocytes replacing the panniculus. Duct-like structures and tubules lined by neoplastic epithelial cells were observed in the primary pancreatic tumour and in the metastatic sites. The aetiology of the fat necrosis was possibly the result of systemic release of lipolytic pancreatic enzymes.     

Feline cerebrovascular disease: clinical and histopathologic findings in 16 cats

Sixteen cats with cerebrovascular disease confirmed via histology to be of nontraumatic and nonneoplastic origins are described. In addition, the anatomy of the arterial supply of the cat's brain is reviewed. It is suggested that this unique arterial design may influence the incidence of cerebrovascular accidents in this species. Of the 16 cats reviewed, seven cats had ischemic infarctions, five had hemorrhagic infarctions, and four were diagnosed with intracranial hemorrhage. The median age was 8 yr and 9.5 yr in cats with infarctions and intracranial hemorrhages, respectively. Clinical signs were severe, acute, consistent with the localization of the cerebrovascular lesion, and influenced by underlying pathology. Four cats with infarction showed lateralized neurologic signs. Four cats with infarctions were diagnosed with pulmonary disease antemortem and three cats had hyperthyroidism. Cerebrospinal fluid analysis and computed tomography scans were available in two cats. None of the infarctions were grossly visible. All cats with hemorrhagic infarcts had severe liver pathology and nephritis was identified in four cats. Hypoxia was a feature in four cats and one cat suffered cardiac failure. In conclusion, the clinical picture is influenced by the type of cerebrovascular disease, the localization of the intracranial lesions, and any underlying pathology.     

Diskospondylitis in a kennel of dogs: clinicopathologic findings

Selected aspects pertaining to the cause and pathogenesis of diskospondylitis were investigated in a kennel of 45 Airedale Terriers. Diskospondylitis was detected via spinal radiography in 17 male and 14 female dogs. Bacteria isolated from the coat, vagina, and urine of affected Airedales were not statistically different from those isolated from clinically normal Airedales. Serologic evidence of Brucella canis infection was not detected. There was no difference in response to thyrotropin stimulation tests between affected and clinically normal dogs. Necropsy findings in affected dogs included hypercellular renal glomeruli and pulmonary arterial thrombi.     

Feline leukemia virus infection and diseases.

Feline leukemia virus is a naturally occurring, contagiously transmitted and oncogenic immunosuppressive retrovirus of cats. The effects of FeLV are paradoxical, causing cytoproliferative and cytosuppressive disease (eg, lymphoma and myeloproliferative disorders vs immunodeficiency and myelosuppressive disorders). In the first few weeks after virus exposure, interactions between FeLV and hemolymphatic system cells determine whether the virus or the cat will dominate in the host/virus relationship--persistent viremia and progressive infection or self limiting, regressive infection will develop. The outcome of these early host/virus interactions is revealed in the diagnostic assays for FeLV antigenemia and viremia. The latter, in turn, predict the outcome of FeLV infection in cats. Known host resistance factors include age and immune system functional status. Known virus virulence factors are magnitude of exposure and virus genotype. Molecular analysis of FeLV strains indicated that natural virus isolates exist as mixtures of closely related virus genotypes and that minor genetic variations among FeLV strains can impart major differences in pathogenicity. The genetic coding regions responsible for cell targeting and specific disease inducing capacity (eg, thymic lymphoma, acute immunosuppression, or aplastic anemia) have been mapped to the virus surface glycoprotein and/or long terminal repeat regions for several FeLV strains. Infection by specific FeLV strains leads to either malignant transformation or cytopathic deletion of specific lymphocyte and hemopoietic cell population, changes that prefigure the onset of clinical illness. Another notable feature of the biology of FeLV is that many cats are able to effectively contain and terminate viral replication, an important example of host immunologic control of a retrovirus infection and a process that can be selectively enhanced by vaccination. Thus, FeLV infection serves as a natural model of the multifaceted pathogenesis of retroviruses and as a paradigm for immunoprophylaxis against an immunosuppressive leukemogenic retrovirus.     

Clinical and clinicopathologic findings in two foals infected with Bacillus piliformis

Bacillus piliformis infection (Tyzzer's disease) in foals is rarely observed clinically because of the peracute course of the disease. Clinical and clinicopathologic findings as well as information on therapeutic attempts in two foals are described. Clinicopathologic abnormalities common to both cases included leukopenia, hyperfibrinogenemia, metabolic acidosis, and hypoglycemia. Treatment was unsuccessful in both cases.