Objective: To identify the prevalence of skin lesions in a population of alpacas in South Australia, and to determine their distribution on the skin surface. Methods: A survey was conducted by professional alpaca shearers over a 16 day period during spring 2013 in three different geographical regions within South Australia. Skin lesions were observed and recorded using a Skin scoring chart, allowing for 11 different lesion types and 15 body areas. Results: Data were available from 338 alpacas, of which 60.4 ± 5.2% had one or more skin lesion. The most commonly observed lesions were scale and lichenification, crust, alopecia and erythema, each observed over 300 times. The most commonly affected areas were the fore and hind legs, axillae and hind feet. There was a significant association between lesion types and their anatomical location (Chi square test, p<0.0001). Conclusion: This survey of a subpopulation of South Australian alpacas has identified skin lesions in approximately 60% of subjects. Based on their location, the majority of lesions observed would not greatly influence the value of the fleece.

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We performed a retrospective histopathological study on the prevalence of hydropic degeneration of epidermal basal cells (strictly defined) in skin-biopsy specimens from 392 cats with various inflammatory dermatoses and 31 cats with normal skin. Hydropic degeneration of epidermal basal cells was significantly associated with a small group of immune-mediated dermatoses characterized by an interface dermatitis histopathological reaction pattern: adverse cutaneous drug reaction, discoid lupus erythematosus, erythema multiforme, exfoliative dermatitis associated with thymoma, and systemic lupus erythematosus. For this group of 5 diagnoses, the prevalence of hydropic degeneration was 35% (95% confidence interval [CI]: 16%, 59%); the other diagnoses had a prevalence of 1.1% (CI: 0.34%, 2.9%) and the healthy cats had a prevalence of 0% (CI: 0%, 14%).

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The objective of this study was to characterize the histological appearance, prevalence, and association of pilosebaceous dysplasia (PD) in dogs with yeast dermatitis. A retrospective, light-microscopic study of H&E-stained skin-biopsy specimens from 670 dogs with non-neoplastic dermatoses and 28 normal dogs was performed. Chi-square and rank-sum analyses were used to compare the prevalence and abundance of PD in dogs with yeast dermatitis, normal dogs, and dogs with non-yeast dermatoses. PD was observed in 76 of 98 (78%; 95%confidence interval (CI) 68%, 85%) of dogs with yeast dermatitis and in 14 of 572 (2.4%; CI 1.4%, 4.2%) dogs with non-yeast dermatoses. PD was not observed in any normal dogs (CI 0%, 15%). The prevalence (presence, yes/no) of PD was significantly greater in dogs with yeast dermatitis (chi-square = 424.49; degrees of freedom = 2; p<0.0001) than in dogs with non-yeast dermatoses and in normal dogs. Also, among the dogs with PD present, the percentage of affected units in each dog was greater (p=0.0002) in dogs with yeast dermatitis (minimum 12%; median75%; maximum 100% affected units/dog) than in dogs with non-yeast dermatoses (minimum 3%; median 30%; maximum 100%). There was no significant difference (p≥0.05) between the prevalence of PD in dogs with non-yeast dermatoses and in normal dogs. These findings suggest that the finding of PD in skin-biopsy specimens of dogs is significantly associated with yeast dermatitis and could be considered when making this histological diagnosis.

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A small cutaneous mass in the right thigh of an 8-year-old, intact male dog was diagnosed as an extraskeletal myxoid chondrosarcoma. Histologically, the neoplasm had lobularity and was characterized by rich myxoid stroma and hypovascularity. The tumor cells displayed polymorphism, and were often arranged in characteristic cords. Immunohistochemically, the tumor cells were positive for vimentin, S-100a, neuron-specific enolase, and synaptophysin. Six months after the surgery, no recurrence or metastasis were observed; however, a large recurrent tumor in the right thigh extending to the abdomen and multiple pulmonary tumors were found in the dog 15 months after the surgery. The necropsy confirmed that the recurrent and pulmonary tumors were the same as the primary tumor and did not involve any cartilage or bone.

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