Squamous cell carcinoma in an American bison (Bison bison bison)

Thermal Injuries in Veterinary Forensic Pathology

Localized thermal injuries in animals may be caused by exposure to fire and radiant heat, contact with hot items including hot liquids or steam, inhalation of hot air, and exposure to cold temperatures. In addition, animal fire victims may have intoxications caused by smoke gas. This article reviews the causes, pathogenetic aspects, morphological findings, additional investigations, differential diagnoses, and causes of death in various forms of thermal injuries. Since these cases do not occur frequently in diagnostic pathology, they represent a challenging task in general but also with respect to forensic or criminal aspects, such as whether a lesion represents an accidental or nonaccidental effect. Besides detailed information about the circumstances at the location, thermal injuries in animals require a thorough morphological evaluation, including additional investigations in conjunction with a profound knowledge about the possible lesion spectrum and suitable additional investigations.

Malignant schwannoma in an American buffalo (Bison bison bison)

A case of a malignant schwannoma in a 20-year-old male American buffalo (Bison bison bison) from the Grand Park Zoo, Gyeonggi Province, Republic of Korea is reported. The animal showed no apparent clinical signs before death except for wound on the neck. Grossly, neoplastic nodules of various sizes were observed on the skin, lung, heart, liver, stomach, mesentery and kidney. Histologically, the neoplastic nodules were composed of fusiform cells that formed multidirectional bundles. The tumour cells were arranged in interlacing bands and bundles. The nuclei were atypical, hyperchromatic, with blunt or round ends. In addition, few mitotic figures were observed in the skin, lung, heart, liver, stomach, intestine and kidney. Several immunohistochemical stains, e.g. vimentin, cytokeratin (CK), smooth muscle actin (SMA), S-100 and HMB45, were used in an attempt to differentially diagnose the tumour. The neoplastic cells tested positive to S-100, but negative to vimentin, CK, SMA and HMB45. Based on the above findings, this case was diagnosed as a malignant schwannoma. To the best of our knowledge, this is the first report of a schwannoma in an American buffalo (B. b. bison).

Chronic hyperplastic and neoplastic cutaneous lesions (Marjolin's ulcer) in hot-brand sites in adult beef cattle

Linear exophytic cutaneous lesions (brand keratomas) are a chronic sequel to hot-iron branding in a small proportion of beef cattle in the western United States. Rarely, brand keratomas progress to form large ulcerated masses. Samples of chronically thickened skin were collected from 8 adult cattle with hot-brand lesions and from 2 cattle with ulcerated masses at brand sites. Cutaneous thickening was attributable to abrupt transition from normal haired skin to regular epidermal hyperplasia with marked orthokeratotic hyperkeratosis, acanthosis, hypopigmentation, and loss of adnexae. Epithelial atypia was absent. Normal dermal collagen was replaced by mature granulation tissue containing islands of dense hyalinized collagen. Two cows, aged 5 and 13 years, developed large, slow-growing squamous cell carcinomas at brand sites. Malignancy in branded skin is a rare complication of hot-iron branding in cattle and may arise because of malignant transformation of brand keratomas.