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.
Factors influencing morbidity and outcome of equine ocular squamous cell carcinoma. A retrospective review of 41 cases of equine ocular squamous cell carcinoma with follow up information for 33 horses is presented. An apparent prevalence in heavy horse breeds was identified. Age and sex distribution were similar to those previously reported. High recurrence (42.4 per cent) and low metastasis (6 per cent) rates were seen. Initial tumour location, primary treatment used, or patient case history had no apparent influence on final outcome. The willingness of owners to pursue with continuous treatment correlated with a high degree of success.
Equine basal cell tumors. Basal cell tumors from 11 horses were examined histologically. Distinct patterns identified in the order of frequency are adenoid (six), solid (three), and medusoid (two). A minor component of most of these neoplasms was a ribbon pattern and cystic spaces. Hyalinized connective tissue and clear cells reminiscent of hair follicle glassy membranes and outer root sheath were present in a solid and the medusoid tumors. Heavy melanin pigmentation was present in one solid basal cell tumor. In eight cases for which information was available, the tumors had not recurred 3 to 8 years after excision.
Clinical course of renal adenocarcinoma associated with hypercupraemia in a horse. A four-year-old shire mare with haematuria, colic, terminal weight loss and an abdominal mass had a large unilateral renal adenocarcinoma. Clinical signs were monitored for 11 months. Increased serum copper concentrations were measured on two occasions. Hypercupraemia is discussed as a possible paraneoplastic change.
Renal carcinoma in a horse. A poorly performing nine-year-old thoroughbred mare was presented because of chronic weight loss. On rectal examination an abdominal mass was palpated and, on percussion of the right flank from the 11th to 13th intercostal space, a large area of dullness was delineated. Biopsies taken from the liver region and through the rectum revealed a malignant metastasising tumour of the urinary system. After euthanasia, the post mortem findings confirmed the presence of a papillary renal carcinoma with multiple metastases into the omentum and peritoneum.
Ocular angiosarcoma in four horses. In 4 horses with ocular angiosarcomas, the common characteristics were that all horses were aged, and the neoplasms developed initially on conjunctival surfaces, grew slowly, and metastasized despite excision and radiation treatment. Histopathologically, the neoplasms were of 2 types: a capillary pattern of scant stroma and endothelial-lined vascular channels, and a solid pattern composed of sheets of pleomorphic cells with hyperchromatic nuclei and poorly defined cytoplasmic borders. Definitive diagnosis was made by use of factor VIII:RAg, which stained the tissues intensely.
Ocular angiosarcoma in the horse: morphological and immunohistochemical studies. Angiosarcomas arising in ocular tissues of four aging horses are described. Tumors were locally invasive and eventually metastasized via the mandibular and cervical lymph nodes. Pathologically, the tumors contained well-differentiated regions, in which vascular channels were lined by pleomorphic endothelial cells, as well as poorly-differentiated regions, in which vascular channels were either rudimentary or absent. Red blood cells were scare in vascular structures formed by the tumors. Factor VIII related antigen (VIII:RAg), a blood vascular endothelial marker, was demonstrated by immunohisto...
Intramuscular hemangiosarcoma with pulmonary metastasis in a horse. Intramuscular hemangiosarcoma resulting in severe anemia and thrombocytopenia was diagnosed in a 3-year-old Thoroughbred filly. Necropsy revealed multiple tumors within skeletal muscles and multiple pulmonary metastases.
Multiple myeloma in a horse. Multiple myeloma was diagnosed in a 22-year-old Arabian mare with a history of chronic weight loss. Quantitative immunoglobulin analysis revealed monoclonal gammopathy (IgG(T), 9,800 mg/dl). Due to progressive weight loss, the horse was euthanatized. Microscopy of tissues revealed plasma cell infiltrates in bone marrow, spleen, pituitary gland, adrenal cortex, muscle of the tongue, and bronchial, renal, and mesenteric lymph nodes.
Malignant melanoma of the coronary band in a horse. A malignant melanoma developed in the digit of a horse. Metastasis was extensive.
Spontaneous expression of an endogenous retrovirus by the equine sarcoid-derived MC-1 cell line. A retrovirus is spontaneously released into the culture medium of the equine sarcoid-derived MC-1 cell line. The MC-1 virus did not exhibit in vitro transforming activity or replication when tested on equine fibroblasts or a variety of other mammalian cell cultures. Complementary DNA, synthesized using detergent-activated MC-1 virus RNA-dependent DNA polymerase, detected homologous sequences in the DNA of an established equine dermal cell line and in the DNA of primary equine dermal fibroblasts. Iododeoxyuridine or azacytidine induced a replication-deficient endogenous retrovirus in the normal...
Effects of horse and fetal calf serum on the expression of tumor-associated antigen and tumorigenicity of L5178Y leukemia/lymphoma cells. A tumor antigen (TA) associated with murine leukemia-lymphoma L5178Y cells has been identified by the enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF) techniques. The antigen was present in both non-solubilized and 0.5% NP-40 solubilized membrane extracts. Rabbit anti-L5178Y lymphoma serum (RALS), extensively absorbed with normal mouse tissues, identified TA in extracts of L5178Y lymphoma and L5178Y leukemia cells grown in horse serum (L5178Y/HS), but not in extracts of L5178Y cells grown in fetal calf serum (L5178Y/FCS). Similarly, absorbed rabbit anti-L5178Y/HS...