Topic:Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) is a type of malignant tumor that arises from squamous epithelial cells, commonly affecting horses' skin, eyes, and mucous membranes. It is one of the most frequently diagnosed cancers in equine species. This carcinoma is associated with prolonged exposure to ultraviolet light, particularly in areas with minimal pigmentation or hair coverage. SCC can present as ulcerated lesions or proliferative masses and may lead to local tissue destruction and metastasis if untreated. Diagnosis typically involves clinical examination, biopsy, and histopathological analysis. Treatment options vary depending on the tumor's location and stage and may include surgical excision, cryotherapy, or chemotherapy. This section aggregates peer-reviewed studies and scholarly articles that explore the pathogenesis, risk factors, diagnostic methods, and treatment approaches for squamous cell carcinoma in horses.
Immunohistochemical detection of P53 overexpression in paraffin wax-embedded squamous cell carcinomas of cattle, horses, cats and dogs. One hundred and six squamous cell carcinomas (SCCs) of cattle, horses, cats and dogs were analysed immunohistochemically for overexpression of p53 protein. The monoclonal antibody pAb 240, which recognizes only mutant p53, was used. Of 41 bovine ocular SCCs, 26 (63.4%) showed p53 nuclear reactivity. All of six (100%) equine ocular SCCs and seven of nine (77.7%) SCCs of the equine penis or vulva gave positive reactions. In nine of 11 (81.8%) feline SCCs of the ear and in seven of 14 (50%) feline SCCs of other locations, p53 immunoreactivity was detected. Only seven of 25 (29.5%) canine cutaneou...
Iridium-192 interstitial brachytherapy for equine periocular tumours: treatment results and prognostic factors in 115 horses. One hundred and fifteen horses with periocular tumours were treated with iridium-192 interstitial brachytherapy. Tumours included squamous cell carcinomas (n = 52) and sarcoids (n = 63). All horses were scheduled to receive 60 Gy (minimal tumour dose) given at a low dose rate (0.034 +/- 0.010 Gy/h). The mean and median follow-up times to last contact or death were 24 and 16 months, respectively. Chronic radiation reactions included palpebral fibrosis (10.4%), cataract (7.8%), keratitis and corneal ulceration (6.9%). Cosmetic changes included permanent epilation (21.7%) and hair dyspigmentation...
Equine model of inducing ulceration in alimentary squamous epithelial mucosa. Ulceration of the gastric squamous epithelial mucosa was induced in 10 horses using a feeding protocol previously shown to expose the gastric mucosa to repeated periods of high acidity. The feeding protocol consisted of alternating feed deprivation with free access to hay. Over a period of seven days, each horse was provided hay for 84 hr and deprived of hay for 84 hr. Hay was never withheld for longer than 24 hr at a time. Gastroscopy was performed on each horse at the beginning of the protocol after 12 hr of feed deprivation, and after a total of 36 hr, 60 hr, and 84 hr of feed deprivation. ...
Management of perianal squamous cell carcinoma with permanent colostomy in a mare. A 28-year-old Pinto mare was evaluated for multiple recurrences of a perianal squamous cell carcinoma. Clinical signs included lethargy, inappetence, weight loss, dyschezia, and hematochezia. The tumor involved the proximal portion of the vulvar labia, the perineum, and the anus, and there was a rectal fistula just left of the anus. Permanent end-on colostomy without further treatment of the carcinoma was the management option chosen. The colostomy functioned satisfactorily, and the mare's condition was stable for the next 14 months. Recurrence of lethargy and inappetence and development of we...
Topical use of 5-fluorouracil for treatment of squamous cell carcinoma of the external genitalia of horses: 11 cases (1988-1992). Ten horses with histologically confirmed squamous cell carcinoma (SCC) and 1 horse with presumptive SCC of the external genitalia were treated with a combination of surgical debridement and topical administration of 5-fluorouracil, or with topical treatment alone. Tumor remission was obtained in all horses except 1 in which owner compliance was deficient, and no recurrences have been reported. Topical use of 5-fluorouracil as a chemotherapeutic agent for treatment of genital lesions of SCC in horses should be considered as a viable alternative to radical surgical excision.
Perioperative intratumoral administration of cisplatin for treatment of cutaneous tumors in equidae. Twenty-seven horses (and 1 mule) with 32 histologically confirmed cutaneous tumors were studied to evaluate the effects of intratumoral injection of cisplatin initiated at the time of surgery. As a result of surgery, 9 of the wounds were closed primarily (5 sarcoids, 4 carcinomas) and 23 were left open to granulate (16 sarcoids, 6 carcinomas, 1 hamartoma). Chemotherapy consisted of 4 treatment sessions of intratumoral injection of cisplatin in purified sesame oil at 2-week intervals. The first treatment session was administered intraoperatively. A controlled-release formulation of cisplatin in...
The cytology of squamous cell carcinomas in domestic animals. A series of 40 tumors with a proven diagnosis of squamous cell carcinoma for which both histology and cytology were available were classified according to their histologic appearance as well differentiated, moderately differentiated, and poorly differentiated. The Romanowsky-stained cytology specimens were reviewed. When available, Papanicolaou-stained smears were included. The cytologic findings for each of the 3 groups are described, and the most significant findings are photographically illustrated.
Squamous cell carcinoma of the larynx and pharynx in horses. Medical records were reviewed for 11 horses with squamous cell carcinoma of the larynx and/or pharynx. The average age at presentation was 15.3 years. No breed or sex predilection was present. At presentation, 6 of 11 horses were dyspneic and 4 horses had inspiratory stridor. Endoscopy was performed in all cases and was more useful in demonstrating a mass in the laryngopharyngeal region than laryngeal or guttural pouch radiography. Surgical excision was attempted in 3 horses and in 1 horse alleviated clinical signs for 4 months. Ten horses were euthanatized and 1 horse died. Results of this st...
Repetitive injectable anesthesia in a 27-year-old horse. A 27-year-old horse was anesthetized 3 times a week for 4 weeks, to facilitate cobalt therapy of a squamous cell carcinoma in the left paranasal sinus. Limitations of facilities required transport of the anesthetized horse to and from the cobalt therapy room, therefore, injectable anesthesia was used. Initially, the horse was preanesthetized with xylazine (at 1.1 mg/kg IV) and butorphanol (0.04 mg/kg IV). After 3 anesthetic episodes, the xylazine dose was reduced to 0.4 mg/kg IV and the butorphanol was deleted from the regimen. Tiletamine-zolazepam (1.1 mg/kg IV) was used for induction and mai...
Clinical and pathological features of thoracic neoplasia in the horse. Thirty-eight horses with confirmed thoracic neoplasia included 28 (37.7%) with lymphosarcoma, 4 (10.5%) with metastatic renal cell carcinoma, 2 (5.3%) with primary lung carcinoma, 2 (5.3%) with secondary squamous cell carcinoma from the stomach, 1 (2.6%) with pleural mesothelioma, and 1 (2.6%) with malignant melanoma. The major clinical features included weight loss, inappetence, dyspnoea and coughing, but in cases of lung metastases, they related more to the primary site of tumour formation. Haematological and serum biochemical abnormalities were non-specific. Specific pre-mortem diagnosis wa...
Neoplasia. Equine tumors are rather uncommon; however, of the body regions, the head is a relatively common location for neoplasia, including sarcoids and squamous cell carcinomas of the skin, tumors of the sinus/nasal cavity, and bony tumors of the head. Tumors discussed in the article include odontogenic and bony tumors; sarcoids; tumors of the guttural pouch and pharyngeal and oral mucosa; tumors of the larynx; and tumors of the paranasal sinuses and nasal passages. In general, tumors involving deeper structures of the head carry a poor prognosis; however, some tumors such as sarcoids, ossifying fibro...
Use of esophagoscopy in the diagnosis of esophageal squamous cell carcinoma in a horse. Esophagoscopy allowed visualization and biopsy of a lesion within a diverticulum of the esophagus in an adult horse. Although the biopsy specimen obtained was small, diagnosis of squamous cell carcinoma was possible from histologic examination of the esophageal tissue sample retrieved by use of endoscopy.
Squamous cell carcinoma associated with a chronic wound in a horse. A 13-year-old Belgian stallion developed a squamous cell carcinoma at the site of a neck laceration that had been treated topically with various irritating chemicals for 18 months. Orthovoltage treatments at 3 times over 5 years controlled the tumor. Eight years after the initial hospitalization, the area was healed and the stallion appeared healthy.
Intratumoral chemotherapy with cisplatin in oily emulsion in horses. Twenty horses with 30 lesions were studied to evaluate the effects of intratumoral chemotherapy with cisplatin in sesame oil on equine sarcoids (n = 19), squamous cell carcinomas (n = 7), and squamous cell papillomas (n = 4). Treatment consisted of 4 sessions of intratumoral cisplatin chemotherapy at 2-week intervals. A controlled-release formulation of cisplatin in sesame oil was used to limit drug egress from the injection site. Mean dosage per session was 0.97 (+/- 0.17, SEM) mg of cisplatin/cm3 of tumor tissue treated for tumor volumes ranging from 10 to 20 cm3. Dosage tended to be slightl...
Hypertrophic osteopathy in three horses and a pony. Hypertrophic osteopathy was diagnosed in 3 horses and in a pony, ranging in age from 8 to 21 years. There were 2 females, 1 sexually intact male, and 1 gelding. In 3 animals, hypertrophic osteopathy was associated with pulmonary abscesses, bronchogenic squamous cell carcinoma, and ovarian granulosa-cell tumor, respectively, and resulted in death or euthanasia. Duration of the condition ranged from 1 to 4 months. In 1 horse, hypertrophic osteopathy was believed to be secondary to pregnancy, and resolved following uncomplicated delivery of a live foal.
Ocular neoplasia. Except for two neoplasms, notably SCC and sarcoid, ocular and periocular tumors are uncommon in horses. The practitioner must accurately determine the type of tumor by histopathology so appropriate treatment and a legitimate prognosis can be offered. The first attempt at treatment has the greatest chance to result in a cure; an aggressive treatment regimen therefore should be selected from the start.
Squamous cell carcinoma of the equine stomach: a report of five cases. Five horses with squamous cell carcinoma of the stomach are described. The clinical findings included anorexia, weight loss, abdominal distension, abnormal chewing and swallowing behaviour and abdominal masses palpable per rectum in four cases. Haematological studies revealed a normocytic anaemia in three horses, and neutrophilia and hypoalbuminaemia in two. Analysis of peritoneal fluid revealed abnormal effusions in all five horses and neoplastic cells were identified in three of them. The tumours originated in the cardia and metastases were present in all the horses. Three of them had many s...
Immunotherapy of periocular squamous cell carcinoma with metastasis in a pony. A 5-year-old Pony of America mare was referred for evaluation of inflamed upper and lower right eyelids. Squamous cell carcinoma of the eyelids and ulcerative keratitis secondary to self-trauma were diagnosed. Initial treatment of the eyelid neoplasia with 2 applications of cryotherapy failed to resolve the lesions, and immunotherapy with bacillus of Calmette-Guerin (BCG) was instituted. Multiple injections of BCG over a 17-week period resulted in progressive shrinkage of the tumor mass, but regional metastasis to the ipsilateral submandibular lymph node occurred. Six months later, ocular neop...
The present status of BCG treatment in the veterinary practice. Horses with sarcoids, cows with ocular squamous cell carcinoma and dogs with mammary tumors were treated with intralesional injection of Bacillus Calmette Guérin. This treatment appeared to be effective in most cases of equine sarcoids, in 50 - 60% of the cows with ocular squamous cell carcinoma and was not effective in dogs with mammary tumors.
Therapeutic management of ocular squamous cell carcinoma in the horse: 43 cases (1979-1989). The records of 50 horses with ocular squamous cell carcinoma (OSCC) presented to the University of Florida Veterinary Medical Teaching Hospital over an 11 year period were reviewed to determine the influence of therapy on the outcome of the case. Follow-up information was obtained for 43 of the 50 cases. The disease was more prevalent in the light horse breeds; however, the draft breeds also were at risk. There was no sex predisposition and the average age was 11.8 years. Tumour recurrence was significant when surgery alone was performed. The eyelid and nictitating membrane were the primary si...
Squamous cell carcinoma as a cause of dyspnea and blindness in a horse. An 8-year-old Quarter Horse mare was examined for chronic nasal discharge and obstruction of both nasal passages. A solid mass lesion was identified in the maxillary sinuses, soft palate, nasal and pharyngeal cavities. Palliative surgery was used to debulk the lesion and facilitate nasal airflow. Squamous cell carcinoma was diagnosed from surgical biopsies. Approximately 7-8 weeks after surgery, the mare was observed to be acutely blind. Ophthalmologic examination revealed central origin blindness and active retinitis. The squamous cell carcinoma had reobstructed the nasal passages. Pressure b...
Excision of oral squamous cell carcinoma in a horse. A large oral squamous cell carcinoma in a 27-year-old Arabian stallion was removed by partial excision of the incisive bone. There was no gross evidence of recurrence or metastasis 5 months later.
Squamous cell carcinoma of the hoof wall in a stallion. Squamous cell carcinoma of the hoof wall, with resultant invasion of the right hind distal phalanx, was identified in a 15-year-old Thoroughbred stallion. The clinical features included a chronic grade 2/5 right hind limb lameness and a sessile dorsal hoof wall mass that was not sensitive to palpation. Radiography revealed a well-circumscribed circular lucency within the distal phalanx, beneath the clinically noticed hoof wall mass. These features were considered to be characteristic of a hoof wall keratoma. Surgical intervention was done 10 months later. The histologic diagnosis at the time o...
Epidemiologic study of ocular/adnexal squamous cell carcinoma in horses. Proportional hospital accession ratios for equine ocular/adnexal squamous cell carcinoma (SCC) were determined for 14 colleges of veterinary medicine participating in the Veterinary Medical Data Program between January 1978 and December 1986. Comparison of the ratios with their respective geographical, physical data has shown an increased prevalence of SCC with an increase in longitude, altitude, or mean annual solar radiation. In contrast, prevalence of SCC increased with a decrease in latitude. Between January 1978 and December 1988, 147 horses with ocular/adnexal SCC were admitted to the Co...
Prognostic factors and survival of horses with ocular/adnexal squamous cell carcinoma: 147 cases (1978-1988). Between January 1978 and December 1988, 147 horses with ocular/adnexal squamous cell carcinoma (SCC) were admitted to the Colorado State University Veterinary Teaching Hospital (CSU-VTH). Diagnosis was confirmed by histologic examination of appropriate tissue specimens. Medical records and communication with owners, referring veterinarians, or both provided information regarding initial examination, treatment at the CSU-VTH, and final outcome. At initial examination, 123 (83.7%) horses had unilateral involvement and 24 (16.3%) horses had bilateral involvement. The nictitating membrane, nasal c...
Squamous cell carcinoma of the equine external genitalia: a review and assessment of penile amputation and urethrostomy as a surgical treatment. A retrospective analysis was performed on 48 cases of suspected neoplasia involving the equine external genitalia. Forty nine squamous cell carcinomata (SCC) and 23 squamous papillomata (SP) were identified. Two cases of epithelial hyperplasia and one case of habronemiasis were also recognised histopathologically. The glans penis was the most common site of tumour development accounting for 53 per cent of cases of SCC and 61 per cent of SP. The urethral diverticulum, urethral process or urethra was involved in 27.6 per cent (8/29) of cases of SCC. Twelve per cent (5/41) of cases of SCC were co...
[Immunotherapy of squamous cell carcinoma of the bovine eye and of equine sarcoid]. Squamous cell carcinomas of the bovine eye and equine sarcoids are briefly reviewed. A single injection of BCG into the tumour results in permanent regression of the lesion in 37 per cent of the cattle, regression followed by recurrence of the tumour in 26 per cent and in progressive growth of the tumour in 37 per cent of the cases. Recurrence may be prevented by repeated injection into the lesion. From 50 to 60 per cent of the cows will remain free from tumours. Equine sarcoids show a complete regression in 70-80 per cent of the cases. Tumours on the limbs show a less satisfactory response (l...
Immunohistochemical detection of papillomavirus structural antigens in animal hyperplastic and neoplastic epithelial lesions. One hundred and seventy-two hyperplastic and neoplastic epithelial lesions from 8 different mammalian and 1 avian species have been tested with an immunohistochemical technique to detect papillomavirus structural antigens. Selected lesions were diagnosed histologically as papilloma, fibropapilloma, equine sarcoid, squamous cell carcinoma, basalioma, epulis, keratoacanthoma, trichoepithelioma, pilomatrixoma, epidermal inclusion cyst, and hyperkeratotic or acanthotic epidermal lesions. Positive nuclear staining was detected in 14 out of 23 papillomas, 8 out of 32 fibropapillomas and in 1 out of ...