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Topic:Cancer
Cancer in horses encompasses a range of neoplastic diseases that affect various tissues and organs in equine species. These conditions involve the uncontrolled growth of abnormal cells, which can form tumors and potentially spread to other parts of the body. Common types of cancer in horses include sarcoids, squamous cell carcinoma, and melanoma, each with distinct characteristics and clinical presentations. Diagnosis often involves a combination of physical examination, imaging techniques, and histopathological analysis. Treatment options vary based on the type and stage of cancer and may include surgical intervention, chemotherapy, and radiation therapy. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathophysiology, diagnostic methods, and treatment strategies for cancer in horses.
Anterior uveal melanoma, with secondary keratitis, cataract, and glaucoma, in a horse. Intraocular melanoma was diagnosed in a 13-year-old horse. Secondary clinical findings included keratitis, cataract, and glaucoma. The eye was enucleated. Follow-up information did not give an indication of metastatic disease.
Common horse sense. This research article corrects a common misconception about the energy metabolism in horses during short sprinting and long-distance running events, emphasizing that short sprints are primarily powered by anaerobic activity, [...]
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...
Primary intra-osseous carcinoma of the maxilla in a horse. An 8-year-old Hannoverian horse developed a swelling of the maxilla caused by a tumour of the hard palate. On histological examination the tumour was diagnosed as a primary intra-osseous carcinoma of the maxilla, a rare odontogenic tumour not previously described in the horse.
Survey of fumonisin production by Fusarium species. Fumonisins B1 (FB1) and B2 (FB2), two structurally related mycotoxins with cancer-promoting activity, were recently isolated from corn cultures of Fusarium moniliforme MRC 826. These toxins have been reported to be produced also by isolates of F. proliferatum. Contamination of foods and feeds by F. moniliforme has been associated with human esophageal cancer risk, and FB1 has been shown to be the causative agent of the neurotoxic disease leukoencephalomalacia in horses. Because of the toxicological importance of the fumonisins, the potential to produce FB1 and FB2 was determined in a study of ...
Colonic adenocarcinoma with osseous metaplasia in a horse. Rectal palpation of a 30-year-old mixed-breed mare with chronic weight loss and intermittent, refractory abdominal pain revealed a mass in the right caudoventral portion of the abdomen. Hematologic and serum biochemical findings were normal except for slight mature neutrophilia and mildly high alkaline phosphatase activity and total bilirubin concentration. Cytologic examination of a specimen obtained by abdominocentesis revealed equal numbers of nondegenerative neutrophils and macrophages, but no evidence of neoplastic cells. The mare continued to have signs of abdominal discomfort and was eu...
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...
[CEA test in domestic animals]. In human cancer treatment, CEA (carcino embryonic antigen) testing is a routine procedure, even though the test is of low sensitivity (40%) and low specificity (70%). Since tests with polyclonal antibodies render no reproducible results with animal sera, the applicability of a recently available monoclonal CEA test designed for human sera was evaluated. We were able to show that the latter test was of supplemental diagnostic value when testing animal sera. The upper normal limit for dogs is 1.65 ng/ml, for cats 2.81 ng/ml, for cows 2.85 ng/ml, for sheep 2.85 ng/ml and for horses 1.61 ng/ml.
[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...
Equine granulosa-theca cell tumors express inhibin alpha- and beta A-subunit messenger ribonucleic acids and proteins. The association of equine granulosa-theca cell tumors with atrophied contralateral ovaries and abnormal estrous cycles suggests that these tumors produce hormones that affect pituitary gonadotropin production. Because inhibin, a heterodimer protein secreted by granulosa cells, decreases FSH production, we examined the presence of inhibin alpha- and beta A-subunits and their mRNAs in ovarian tumors obtained from three mares. These tumors contained neoplastic cords and nodules, multiple fluid-filled cysts, and a predominance of neoplastic granulosa cells. Reduced proteins from tumor-conditioned ...
Pleural effusion secondary to thoracic metastatic mammary adenocarcinoma in a mare. A 17-year-old Quarter Horse mare was examined nearly 3 years after excision and cryotherapy of a papillary mammary gland adenocarcinoma. The mare had been used for pleasure riding since surgery, but had recently developed progressive dyspnea. The mare had clinical evidence of pleural effusion, but died before further clinical examination and treatment were instituted. Necropsy revealed deep mammary masses with similar nodules in the deep inguinal, renal, and mediastinal lymph nodes and in the lungs, pericardium, visceral and parietal pleurae, and left ovary. The masses were identified as papil...
Two rare cutaneous neoplasms in horses: apocrine gland adenocarcinoma and carcinosarcoma. Two rare equine cutaneous neoplasms, an apocrine gland adenocarcinoma and a carcinosarcoma were diagnosed in a 17-year-old pony and a 14-year-old mare, respectively. The apocrine gland adenocarcinoma was present on the prepuce. Histologically, papillary projections of low cuboidal to columnar epithelial cells were generally well differentiated, and surrounded dilated acini. Stromal invasion was present, but vascular and lymphatic invasion was not seen. The carcinosarcoma was present in the right flank of the mare. Two discrete cell populations were characterized histologically. One portion of ...
Malignant melanoma in the foot of a horse. A 24-year-old horse had a malignant melanoma of the right forefoot. Because surgical excision of the melanoma was incomplete, as determined by histologic examination of the excised tissue margins, the tumor margins were injected with a matrix therapeutic implant containing cis-diamminedichloroplatinum, epinephrine, and purified bovine collagen matrix. The foot healed and the horse remained clinically free of disease for 26 months before recurrence of malignant melanoma. Surgical exploration of the digit revealed extensive involvement of the foot, and the horse was euthanatized.
Treatment of advanced squamous cell carcinomas involving the equine cornea. Corneal squamous cell carcinomas with surface areas of more than 2.0 cm were diagnosed in 26 eyes of 25 horses. The depth of the lesion into the corneal stroma and involvement of the ocular adnexa were important determinants for surgical treatment. Corneal tumors that extended into adjacent palpebral conjunctiva, eyelid, or orbit were not amenable to complete excision, while those that involved only cornea and bulbar conjunctiva were treated surgically by keratectomy and beta radiation. Initial treatment was keratectomy followed by beta radiation on 24 eyes and enucleation of two eyes. Twenty ...
Combined treatment of ocular squamous cell carcinoma in a horse, using radiofrequency hyperthermia and interstitial 198Au implants. Unilateral ocular squamous cell carcinoma in a horse was treated effectively with a combination of repeated radiofrequency hyperthermia and interstitial radiotherapy. These 2 modalities of treatment are synergistic. Interstitial irradiation was achieved, using 198Au implants to deliver a total dose of approximately 5,000 rads/implant over an area of 1 cm2. Radio frequency hyperthermia was repeated 3 times, and radiotherapy was used twice. Treatment resulted in complete regression of the tumor, and ocular complications have not been seen.
Pleuroscopic diagnosis of disseminated hemangiosarcoma in a horse. A 7-year-old Thoroughbred mare was examined because of persistent bilateral epistaxis and respiratory distress. Evidence of bilateral pleural effusion was found during physical examination, and a large amount of serosanguineous fluid was drained from the right side of the thorax. Cytologic examination and bacteriologic culture of the transtracheal aspirate and pleural fluid did not yield evidence of sepsis. A coagulation profile was unremarkable. Radiographic and echographic changes were seen in the lung parenchyma. Pleuroscopy, with the horse standing, revealed numerous dark nodules on the pl...
Pseudohyperparathyroidism in a mare associated with squamous cell carcinoma of the vulva. An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of...
Carbon dioxide laser ablation for treatment of limbal squamous cell carcinoma in horses. Limbal squamous cell carcinoma in 4 horses was treated successfully, using carbon dioxide laser ablation. Tumors were removed, with minimal to no postoperative inflammation or discomfort to the horses. Carbon dioxide laser ablation represents a promising new option in the treatment of limbal squamous cell carcinoma in horses.
Hepatocellular carcinoma associated with erythrocytosis and hypoglycemia in a yearling filly. A yearling Arabian-type filly with a history of poor growth, erythrocytosis, hypoglycemia, and high liver enzyme activities was admitted to the hospital for evaluation. Three days after admission, the filly collapsed, deteriorated rapidly despite treatment, and was euthanatized. A metastatic hepatocellular carcinoma with capsular rupture and hemoperitoneum were found at necropsy. Primary liver tumors are rare in horses, and hepatocellular carcinoma has been reported in only 1 other horse. The systemic manifestations of the tumor in this filly included weakness, weight loss, inappetence, erythr...
