Burn-induced neoplasia in two horses

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.

Inflammation and cancer: a comparative view

Rudolph Virchow first speculated on a relationship between inflammation and cancer more than 150 years ago. Subsequently, chronic inflammation and associated reactive free radical overload and some types of bacterial, viral, and parasite infections that cause inflammation were recognized as important risk factors for cancer development and account for one in four of all human cancers worldwide. Even viruses that do not directly cause inflammation can cause cancer when they act in conjunction with proinflammatory cofactors or when they initiate or promote cancer via the same signaling pathways utilized in inflammation. Whatever its origin, inflammation in the tumor microenvironment has many cancer-promoting effects and aids in the proliferation and survival of malignant cells and promotes angiogenesis and metastasis. Mediators of inflammation such as cytokines, free radicals, prostaglandins, and growth factors can induce DNA damage in tumor suppressor genes and post-translational modifications of proteins involved in essential cellular processes including apoptosis, DNA repair, and cell cycle checkpoints that can lead to initiation and progression of cancer.

Multiple eccrine poromas in the paw of a dog

A 5-year-old, spayed female boxer dog presented to the referring veterinarian with a year-long history of swelling, ulceration and pain in the pawpad of the fourth digit of the right forelimb. Histologically, the pawpad was expanded by a mass composed of small polygonal cells forming broad bands and trabeculae within the lower epidermis that often infiltrated and replaced the overlying keratinocytes and that extended into the dermis. Lobules of eccrine glands within the deep dermis occasionally had one or more eccrine ducts that were lined by neoplastic ductal epithelial cells that formed papillary projections lined by one to two layers of neoplastic cells. Approximately 1 month after amputation of the fourth digit pad, several smaller nodular masses developed in multiple digital pads and the metacarpal pad of the same paw. All of the neoplasms were histologically identical to eccrine poroma (juxtaepidermal acrospiroma), a common benign neoplasm in humans that originates from the acrosyringium and upper dermal duct of eccrine glands. To the authors' knowledge this is the first report documenting an eccrine poroma in a dog.

Myofibroblastic fibrosarcoma with multifocal osseous metaplasia at the site of equine influenza vaccination

We describe a fibrosarcoma in a 12-year-old Quarterhorse x Arabian gelding as a sequela to equine influenza vaccination. Shortly after the second vaccination, swelling at the site was noticed by the owner and it continued to increase in size over the following 6 months. Biopsy of the mass indicated a fibrosarcoma had developed at the vaccination site. It was approximately 20 cm in diameter and elevated well above the level of the skin. There was no clinical evidence of metastases to the lungs or local lymph nodes. Surgical resection of the mass was performed and the wound healed by first and second intention. Histopathological examination and immunohistochemical staining confirmed a myofibroblastic fibrosarcoma with multifocal osseous metaplasia. To the authors' knowledge, this is the first equine case of a vaccine-associated fibrosarcoma.

Complications of equine wound management and dermatologic surgery

Complications of wounds and cosmetic surgery can be accurately managed with a combination of timely surgical and medical intervention to ensure the best possible outcome. The lack of soft tissue protection and a large quantity of susceptible synovial, tendon, ligament, and neurovascular structures make early and meticulous evaluation of limb wounds critical. Skin grafting is usually used following a period of open wound management and after healthy granulation tissue formation. Penetrating wounds of the abdomen or thorax have a guarded prognosis resulting from the ensuing potential for infection and pneumothorax. Gunshot wounds limited to the skeletal muscles have a good prognosis, whereas injuries that involve vital organs decreased survivability.

Management of burn injuries in the horse

Extensive thermal injuries in horses can be difficult to manage. The large surface of the burn dramatically increases the potential for loss of fluids,electrolytes, and calories. Burns are classified by the depth of injury: first-degree burns involve only the most superficial layers of the epidermis;second-degree burns involve the entire epidermis and can be superficial or deep; third-degree burns are characterized by loss of the epidermal and dermal components; and fourth-degree burns involve all the skin and underlying muscle, bone, and ligaments. Burns cause local and systemic effects. Routine use of systemic antibiotics is not recommended in burn patients. Topical medications should be water based, be easily applied and removed, not interfere with wound healing, and be readily excreted or metabolized. Weight loss of 10% to 15% during the course of illness is indicative of inadequate nutritional intake. Gradually increasing the grain,adding fat in the form of vegetable oil, and offering free-choice alfalfa hay increase caloric intake.

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.

Dermatologic tumors (excluding sarcoids)

Cutaneous neoplasia represents a clinical problem with which veterinarians are commonly challenged. This article addresses equine cutaneous squamous cell carcinoma, squamous cell papilloma, melanoma, mastocytosis, and lymphosarcoma. Current concepts regarding the origin, pathogenesis, diagnosis and treatment of each neoplasm is emphasized.

Skin tumours in cattle and sheep after freeze- or heat-branding

This article describes the occurrence of carcinogenic epidermal neoplasia (papillomas and squamous cell carcinoma) at the sites of tattooing with liquid nitrogen in dairy cattle, and squamous cell carcinoma at the sites of freeze- or heat-branding in beef cattle and sheep.