Carcinoma de células escamosas em suínos com dermatose solar

Abstract

Squamous cell carcinoma (SCC) is a malignant neoplasm originating from epidermal keratinocytes that stimulate their differentiation and replication disorderly. Exposure to ultraviolet light is the most significant risk factor in the development of SCC, particularly in hairless and/or depigmented areas of the skin. It can affect all domestic animals and is considered rare in swine species. Diagnosis is made through histopathological examination, although early or pre-neoplastic changes may be subtle even in histopathology. Solar dermatosis is a condition that shares the same risk factors as SCC, and the occurrence of this type of tumor from its incipient or pre-neoplastic lesions and its pathogenesis is well described, especially in humans and companion animals. The aim of this study was to describe the epidemiological, clinical, and anatomopathological findings of two outbreaks of SCC in pigs with solar dermatosis. In this sense, this thesis is divided into two sections: the first provides a literature review on dermatopathies diagnosed in pigs, and the second comprises an article entitled "Squamous Cell Carcinoma in Pigs with Solar Dermatosis." The first outbreak described refers to the involvement of 14 animals from a herd of 578 pigs of Pietrain and Large White breeds in different production phases (2.4%), from Boqueirão, Paraíba state. The second outbreak refers to the involvement of 3 animals from a herd of 79 pigs of Pietrain and Large White breeds in the gestation phase (3.8%), from Areia, Paraíba state. Macroscopically, the skin lesions were characterized by alterations on the head, back, flank, ears, and tail, with a history of occurrence for more than 3 months (outbreak 1), and ulcerated nodules located on the back, head, ears, flank, and scattered throughout the body for more than a year (outbreak 2). In both cases, skin biopsies were collected and sent to the Veterinary Pathology Laboratory. Microscopically, ulceration, inflammation, and infiltration in the tissue adjacent to the epidermis, presence of keratinocyte trabeculae, nests, dyskeratosis, keratin-filled cells with abundant cytoplasm, sometimes united and forming extensively distributed keratin pearls, characteristic of in situ SCC. The delay in seeking care, as reported in this study, coupled with the inadequate housing conditions in which the animals were found, may have contributed to the onset of tumors, as chronic sun exposure is an important factor in their development.