Squamous Cell Carcinoma in the Third Eyelid of a Dog

Background: Squamous cell carcinoma is a malignant neoplasm that originates from the keratinized stratified squamous epithelium and predominantly affect light-skinned animals. In dogs, breeds such as American Staffordshire Terriers, white or speckled Bull Terriers, and Beagles have a higher predisposition. Squamous cell carcinoma presents in the skin, at slightly pigmented or hairy sites, especially in digits, but also may occur in the nasal planum, oral mucosa, and rarely, in the eye. Considering that few reports have been published on eye neoplasms, the aim of this paper is to describe a dog with a lesion in the third eyelid of his right eye which was diagnosticated with squamous cell carcinoma. Case: A 10-year-old male American Staffordshire dog was admitted to the Veterinary Medical Teaching Hospital of the Veterinary Medicine and Zootechnics College, Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil with injury to the right eye. During the physical examination, there was also a non-adhered lump near the foreskin, measuring 1.5 cm in diameter. In addition, there was another lump in the third eyelid of the right eye, approximately 3 mm in diameter. Cytology of the dermal nodule was performed by fine-needle aspiration cytology; however, the sample was insufficient for cytological evaluation. Therefore, the animal was placed under general anesthesia for skin lump excision and for fine-needle aspiration cytology of the third eyelid nodule. The histopathological exam revealed high cellularity of epithelial cells, intense anisocytosis and pleomorphism, cytoplasmic basophilia and vacuolation, multiple evident nucleoli, and anisocariosis and coarse chromatin. These finds were compatible with squamous cell carcinoma, which was the same result suggested by fine-needle aspiration cytology of the third eyelid sample. Based on these results, the dog underwent a surgical procedure for enucleation and subsequent histopathological evaluation of the nodule in the third eyelid, which confirmed the squamous cell carcinoma diagnosis.Discussion: Squamous cell carcinoma is an extremely aggressive tumor with low metastatic potential, characterized by invasion of the dermis by proliferation of malignant epithelial cells from the prickly layer. It is most common in elderly animals, and American Staffordshires are among the breeds that are predisposed to develop this tumor. The clinical presentation is highly variable, depending on the tissue involved. In this case, the dermal nodule was an elevated area on the skin and the third eyelid nodule resembled an ulcerative mass. Cytological examination from the lesion located on the third eyelid, showed malignancies cytoplasmic changes frequently found in carcinomas such as anisocytosis, cytoplasmic basophilia, and cell pleomorphism. In addition, nuclear changes had also occurred, such as crass chromatin, multiple evident nucleoli, and multinucleated cells. A presumptive diagnosis was made based on cytology and was confirmed after biopsy and histopathological examination. Because it is uncommon in dogs, squamous cell carcinoma of the third eyelid may be misdiagnosed, delaying correct treatment, and accelerating the development of the tumor. Currently, various therapeutic approaches are available, such as surgical excision, electrosurgery, cryosurgery, radiation, and hyperthermia. The choice of treatment depends on the location and stage of the lesions. Surgical treatment should be aimed at removing sufficient tissue to leave surgical margins free of neoplastic cells

Vaginal Squamous Cell Carcinoma in a Nelore cow

Background: Skin tumors are the most common neoplasia in veterinary medicine and squamous cell carcinoma (SCC) is the most frequent. In cattle, it is the main tumor besides linfosarcoma and normally affects taurine cattle, but is rare in Nelore cattle. SCC mainly affects mucocutaneous junctions such as the eyelids, sclera, vulva, and perineum, and has already been described in vaginal, eye, and periocular tissues, in addition to the superior digestive tract. The purpose of this paper is to describe a vaginal squamous cell carcinoma in a Nelore cow.Case: A 10-year-old Nelore cow, used as an embryo donor, was submitted to a necropsy procedure. Clinically, the animal had prolonged recumbency, anorexia, weight loss, and vaginal discharge. There was a history of recurrent vaginal prolapses and an intraluminal vaginal mass that had grown over two years. At necropsy, there was diffuse fibrinous peritonitis with marked intestinal adhesions; the vagina was markedly expanded and measured 40 × 20 cm due to the presence of an intraluminal mass occupying the vestibulum and extending up to the cervix. In the vaginal lumen, there was large amount of fibrinonecrotizing malodorous material; the vaginal wall was thickened by an unencapsulated and poorly delimited, firm and white mass composed of sheets and nests of epithelial cells from the squamous layer surrounded by abundant fibrovascular stroma. The neoplastic cells were polygonal with marked pleomorphism, anisokariosis, and anisocytosis; abundant; eosinophilic; and had well-defined cytoplasmic borders. Sometimes it was possible to see desmosomes. The nuclei were rounded to oval with sparse chromatin and one or more nucleoli were seen. Mitotic figures were frequent (at least 3 per higher power field) and there were also a few multinucleated cells. Frequently, there was the formation of distinct keratin “pearls”.Discussion: SCC frequently occurs in the skin, eyes, and vulva in cattle, since these are sites that lack pigment within the epidermis and have prolonged exposed to ultraviolet light. Vaginal SCC has already been described in one cow with recurrent vaginal prolapses that was submitted to follicular aspiration. In a survey of cattle tumors, most genital tract neoplasias affected the uterus, and vaginal tumors normally originated from connective tissue - fibromas, fibropapillomas, and fibrosarcoma - or muscular tissue - leiomyoma and leiomyosarcoma. Irreversible changes in cellular DNA can occur due to physical or chemical carcinogens, and also chronic inflammation. The cow in this paper was frequently submitted to follicular aspiration and this can cause chronic inflammation in the vaginal mucosa after the puncture and, when it’s chronic, can represent one of the main initiating factors for tumor development. This cow’s death was caused by diffuse and marked peritonitis. The same cause was previously described in cows submitted to follicular aspiration and, in one of these animals, there was a rectal perforation caused by mistakes during the procedure. In this animal, we did not find any lesions in the rectum or intestines, however, considering the gravity of the peritonitis, we were not able to exclude this hypothesis. Papillomavirus has previously been found in SCC in sheep and probably acts synergistically with ultraviolet light, however, in this animal, we did not test for the virus. Squamous cell carcinoma in an uncommon tumor in cows’ vaginas, however, this should be included as a possible differential diagnosis, especially in animals submitted to situations that can cause chronic inflammation in the genital tract

Photosensitization in Cattle Caused by Spontaneous and Experimentally Ingestion of Stryphnodendron fissuratum

Background: Stryphnodendron fissuratum is a tree from the Brazilian Cerrado. Its fruit is toxic to cattle and can cause clinical digestive signs, hepatogenous photosensitization, and abortion. Cases of poisoning in cattle, goats and guinea pigs have been experimentally reproduced; however, photosensitization could not be reproduced. The aim of this work was to describe an outbreak of natural poisoning and experimental reproduction in cattle, both with hepatogenous photosensitization.Materials, Methods & Results: Its described and natural outbreak and an experimental poisoning. In the outbreak, three bovines in the acute phase and three in the chronic phase were examined. Blood samples were collected from all of these animals in order to measure serum levels of aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), urea, and creatinine. The first three animals underwent necropsy and histopathological evaluation. The experiment was conducted with two nine-month-old calves that received an oral paste made with crushed S. fissuratum fruits mixed with water. These fruits were collected at a farm at which cattle poisoning cases had occurred. Blood samples were collected in order to measure serum levels of AST, GGT, urea, and creatinine, before plant administration and then daily during the experimental period. Skin biopsies were taken before plant administration and new one after the first signs of skin lesions. The natural outbreak affected 52 of 160 bovine (31 calves and 21 cows) in the lot. Two calves and 14 cows died. Clinical signs consisted of depression, ataxia, incoordination, behavioral changes, decubitus, and death. One animal that died and 36 others that recovered had photodermatitis. Necropsy findings in the animals consisted of bad corporal condition, pale kidneys, evidence of liver lobular pattern, dry rumen contents, and full bladder. In two animals, fruit seeds were found in the rumen, and one animal had ulcers and transmural edema in the abomasum. Microscopically, mild to moderate renal tubular distension, accumulation of proteinaceous material in lumen with mild to moderate swelling, and epithelial necrosis. In the liver, swelling of hepatocytes and moderate bile stasis was detected. Enzymes values in all evaluated bovines were higher than those considered normal for the species. Experimentally, both calves became ill and one died. The clinical signs were apathy, inappetence, wobbling, weight loss, and goosebumps. One of them had jaundice, tearing, photophobia, ear skin detachment, and ulcers at the muzzle, nostrils and ventral face of the tongue. This animal was euthanized in extremis, and the necropsy findings showed generalized jaundice, evidence of increased liver lobular pattern, thick bile, pale kidneys, and esophageal, tongue, and epiglottal ulcers. Microscopically, the lesions were similar to those described during the natural outbreak. The skin biopsy from the calf that recovered showed perivascular edema and mild eosinophilia.Discussion: The diagnosis was made based on clinical signs, necropsy findings, histopathological lesions, and epidemiological analysis. Experimentally, the plant was toxic at the administered doses. Photosensitization was the most common clinical sign during the natural outbreak and until now, has never been experimentally reproduced. Based on histopathological lesions observed in this study, we can consider that is from hepatogenous origin. The results showed that the kidney lesions have an important role during the pathogenesis caused by this poisoning and during disease evolution

Squamous Cell Carcinoma in the Third Eyelid of a Dog

Background: Squamous cell carcinoma is a malignant neoplasm that originates from the keratinized stratified squamous epithelium and predominantly affect light-skinned animals. In dogs, breeds such as American Staffordshire Terriers, white or speckled Bull Terriers, and Beagles have a higher predisposition. Squamous cell carcinoma presents in the skin, at slightly pigmented or hairy sites, especially in digits, but also may occur in the nasal planum, oral mucosa, and rarely, in the eye. Considering that few reports have been published on eye neoplasms, the aim of this paper is to describe a dog with a lesion in the third eyelid of his right eye which was diagnosticated with squamous cell carcinoma. Case: A 10-year-old male American Staffordshire dog was admitted to the Veterinary Medical Teaching Hospital of the Veterinary Medicine and Zootechnics College, Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil with injury to the right eye. During the physical examination, there was also a non-adhered lump near the foreskin, measuring 1.5 cm in diameter. In addition, there was another lump in the third eyelid of the right eye, approximately 3 mm in diameter. Cytology of the dermal nodule was performed by fine-needle aspiration cytology; however, the sample was insufficient for cytological evaluation. Therefore, the animal was placed under general anesthesia for skin lump excision and for fine-needle aspiration cytology of the third eyelid nodule. The histopathological exam revealed high cellularity of epithelial cells, intense anisocytosis and pleomorphism, cytoplasmic basophilia and vacuolation, multiple evident nucleoli, and anisocariosis and coarse chromatin. These finds were compatible with squamous cell carcinoma, which was the same result suggested by fine-needle aspiration cytology of the third eyelid sample. Based on these results, the dog underwent a surgical procedure for enucleation and subsequent histopathological evaluation of the nodule in the third eyelid, which confirmed the squamous cell carcinoma diagnosis.Discussion: Squamous cell carcinoma is an extremely aggressive tumor with low metastatic potential, characterized by invasion of the dermis by proliferation of malignant epithelial cells from the prickly layer. It is most common in elderly animals, and American Staffordshires are among the breeds that are predisposed to develop this tumor. The clinical presentation is highly variable, depending on the tissue involved. In this case, the dermal nodule was an elevated area on the skin and the third eyelid nodule resembled an ulcerative mass. Cytological examination from the lesion located on the third eyelid, showed malignancies cytoplasmic changes frequently found in carcinomas such as anisocytosis, cytoplasmic basophilia, and cell pleomorphism. In addition, nuclear changes had also occurred, such as crass chromatin, multiple evident nucleoli, and multinucleated cells. A presumptive diagnosis was made based on cytology and was confirmed after biopsy and histopathological examination. Because it is uncommon in dogs, squamous cell carcinoma of the third eyelid may be misdiagnosed, delaying correct treatment, and accelerating the development of the tumor. Currently, various therapeutic approaches are available, such as surgical excision, electrosurgery, cryosurgery, radiation, and hyperthermia. The choice of treatment depends on the location and stage of the lesions. Surgical treatment should be aimed at removing sufficient tissue to leave surgical margins free of neoplastic cells