Tumors in horses are abnormal growths of tissue that result from uncontrolled cell division. They can be benign or malignant and may affect various tissues and organs within the equine body. Common types of tumors in horses include sarcoids, melanomas, and squamous cell carcinomas. The presence and progression of tumors can impact a horse's health, performance, and quality of life. Diagnosis often involves clinical examination, imaging techniques, and histopathological analysis. This page compiles peer-reviewed research studies and scholarly articles that explore the types, diagnosis, treatment options, and prognostic factors associated with tumors in equine medicine.
Porcellato I, Mecocci S, Mechelli L, Cappelli K, Brachelente C, Pepe M, Orlandi M, Gialletti R, Passeri B, Ferrari A, Modesto P, Ghelardi A....Penile squamous cell carcinomas (SCCs) are common tumors in older horses, with poor prognosis mostly due to local invasion and recurrence. These tumors are thought to be mainly caused by papillomavirus type 2 (EcPV-2). The aim of this study is to characterize the tumor immune environment (TIME) in equine penile tumors. Equine penile epithelial tumors (17 epSCCs; 2 carcinomas , CIS; 1 papilloma, P) were retrospectively selected; immune infiltrate was assessed by histology and immunohistochemistry; RT-qPCR tested the expression of selected chemokines and EcPV-2 DNA and RNA. The results confirme...
Pettersson CM, Broström H, Humblot P, Bergvall KE.Equine sarcoids are the most prevalent skin neoplasm in horses worldwide. Although several treatments are available, none are consistently effective and recurrence is common. Objective: To evaluate the efficacy and safety of topical imiquimod 5% cream and Sanguinaria canadensis + zinc chloride for treatment of equine sarcoids and investigate possible systemic effects on distant untreated sarcoids. Unassigned: Twenty-five client-owned horses with a total of 164 tumours were included in the study. Fifty-seven tumours were treated and 107 tumours were left untreated. Methods: Skin biopsy sample...
Behrendt D, Burger D, Gremmes S, Szunyog K, Röthemeier S, Sieme H.Stallion-like or aggressive behaviour in mares affected by unilateral granulosa theca cell tumour (GTCT) is well-known, but use of a GnRH-vaccine as an alternative to surgical removal of the neoplastic ovary has not been investigated. Objective: To determine the effect of immunisation against GnRH on ovarian size, testosterone concentration, Anti-Müllerian hormone (AMH) concentration, and owner-reported behaviour in four mares affected by unilateral GTCT. Methods: Retrospective case report. Methods: A presumptive diagnosis of GTCT was made in four mares based on clinical signs, behavioural ch...
Billi T, Karadima V, Tyrnenopoulou P, Apostolopoulou EP, Brellou GD, Diakakis N.A 20-year-old grey Warmblood gelding that had history of dermal melanomatosis. To report surgical treatment of a 6-cm large malignant metastatic melanoma located in the cutaneous trunci muscle of the left lateral thorax of a horse. A 20-year-old grey Warmblood gelding was referred for evaluation of a large, rapidly growing, thoracic mass. Clinical examination revealed an ovoid, firm, non-painful, movable mass, approximately 6 cm in diameter, located in the cutaneous trunci muscle of the left lateral thorax. Multiple melanocytic nodules were also found at the perianal region and ventral tail. ...
De Ridder T, Ruppin M, Wheeless M, Williams S, Reddell P.Tigilanol tiglate is a novel small molecule approved as a veterinary pharmaceutical in Europe for intratumoural treatment of non-metastatic, non-resectable canine mast cell tumors. The drug has a "tumor agnostic" mode of action associated with induction of an acute inflammatory response at the treatment site, immune cell recruitment, and disruption of tumor vasculature. Consequently, tigilanol tiglate has potential in treating a range of tumor types in humans and companion animals. However, it is likely that species-specific dosing and concomitant medication protocols will be required, especia...
Abu-Seida AM, Shamaa AA.Congenital frontal osteoma has not been previously described in horses. This report records-for the first time-a congenital osteoma of the frontal bone in a 4-month-old Arabian filly. The filly had a frontal hard mass that was present at birth and then showed a slow and continuous growth. This mass appeared as a solitary, painless, oval dense tumor of compact bone, about 2 cm in diameter and 3 cm in length. The tumor was asymptomatic, and the skin over the mass was normal. Radiography revealed a well-defined oval, radio-dense mass projecting from the surface of the right frontal bone with no...
Semik-Gurgul E.Sarcoids are the most commonly diagnosed skin tumours in equines. Bovine papillomaviruses (BPVs) are the primary causative agent of sarcoids. There has been intensive research to discover the molecular mechanisms that may contribute to the aetiopathogenesis of this disease and tumour suppressors and proto-oncogenes known to play a role in human neoplastic conditions have been investigated in equine sarcoids. Current approaches include the identification of gene expression profiles, characterising sarcoid and normal skin tissues, and an assessment of epigenetic alterations such as microRNA diff...
van der Weyden L, Brenn T, Patton EE, Wood GA, Adams DJ.In contrast to other cancer types, melanoma incidence has been increasing over the last 50 years, and while it still represents less than 5% of all cutaneous malignancies, melanoma accounts for the majority of skin cancer deaths, due to its propensity to metastasise. Whilst melanoma most commonly affects the skin, it can also arise in mucosal surfaces, the eye, and the brain. For new therapies to be developed, a better understanding of the genetic landscape, signalling pathways, and tumour-microenvironmental interactions is needed. This is where animal models are of critical importance. The ...
Peters-Kennedy J, Lange CE, Ortved K.Aural plaques are associated with and thought to be caused by one or more Equus caballus papillomaviruses (EcPV). Aural plaques have not previously been reported to be associated with squamous cell carcinoma (SCC). Objective: To describe a horse with aural plaques and squamous cell carcinoma (SCC) on the right pinna. Methods: A 28-year-old thoroughbred gelding presented for multiple plaques and a mass on the right pinna. Methods: Pinnal resection, histopathological investigation, multiple conventional PCRs for papillomavirus DNA and Sanger sequencing were performed. Results: Multiple, raised, ...
Renaudin CD, Kelleman AA, Keel K, McCracken JL, Ball BA, Ferris RA, McCue PM, Dujovne G, Conley AJ.Granulosa cell tumours (GCT) are the most common ovarian tumours in mares. While the classical presentation may not represent diagnostic challenges, diagnosis is not easy in the early stages. Objective: Illustrate the variability in the presentation and serum biomarkers associated with ovarian abnormalities in the mare. Methods: Retrospective case series. Methods: Nonclassical cases of GCTs and other ovarian conditions were identified and behaviour, GCT endocrine results, palpation and ultrasonographic findings are described and the diagnostic value of each is discussed. Results: Mares in this...
Porcellato I, Modesto P, Cappelli K, Varello K, Peletto S, Brachelente C, Martini I, Mechelli L, Ferrari A, Ghelardi A, Razzuoli E.In horses, squamous cell carcinomas (SCCs) are the most common malignant tumors developing on non-pigmented skin, muco-cutaneous areas, like external genitalia, and, less frequently, in the stomach. Growing evidence suggests Equus caballus papillomavirus type 2 (EcPV2) as causative agent of genital SCCs. Our case report describes a 20-year-old, female, mixed-breed pony with co-occurring vulvar papilloma and in situ carcinoma and gastric SCC. Both lesions were positive for the same EcPV2, as confirmed by DNA sequencing. E6 mRNA expression was observed both in vulvar lesions and gastric SCC, whi...
Podstawski P, Witarski W, Szmatoła T, Bugno-Poniewierska M, Ropka-Molik K.Sarcoids are the most common skin neoplasm in the Equidae family. Sarcoids are benign, but may cause severe damage in affected animals. Due to the high risk of post-treatment recurrence and the lack of an effective method of treatment, it is reasonable to perform studies on the molecular aspects of this neoplasm. Therefore, the present studies analyzed five genes (cell cycle control binding protein alpha, coronin 1b, metalloproteinase 2, tissue inhibitor of metalloproteinases 3 and vimentin) related to cell mobility and invasion traits. Primary healthy fibroblasts and sarcoid cells were obtain...
Arthurs C, Suarez-Bonnet A, Willis C, Xie B, Machulla N, Mair TS, Cao K, Millar M, Thrasivoulou C, Priestnall SL, Ahmed A.Equine penile squamous cell carcinoma (EpSCC) is a relatively common cutaneous neoplasm with a poor prognosis. In this study, we aimed to determine the protein expression and colocalisation of FRA1, c-Myc, Cyclin D1, and MMP7 in normal (NT), tumour (T), hyperplastic epidermis and/or squamous papilloma (Hyp/Pap), poorly-differentiated (PDSCC), or well-differentiated (WDSCC) EpSCC using a tissue array approach. Further objectives were to correlate protein expression to (i) levels of inflammation, using a convolutional neural network (ii) equine papillomavirus 2 (EcPV2) infection, detected using ...
Cavasin JP, Miller AD, Duhamel GE.An 8-year-old Anglo-European gelding with progressive neurological signs was humanely destroyed and submitted for necropsy examination. The right parietal cortex was disrupted by a well-demarcated, intraparenchymal, 1.5 cm diameter, tan, homogeneous, dense mass. Microscopical examination was consistent with an astrocytoma, which was confirmed on the basis of strong immunohistochemical labelling for glial fibrillary acidic protein. The neoplastic population lacked immunolabelling for oligodendrocyte transcription factor 2. Labelling for ionized calcium binding adaptor molecule 1 highlighted la...
Caston SS, Sponseller BA, Dembek KA, Hostetter JM.A reformulation of Mycobacterium cell wall fraction immunotherapeutic can be used to successfully treat sarcoids in horses. Sarcoids are reported to be the most common equine skin tumors with tumor type and location influencing the choice of treatment. Wide surgical excision is curative for many tumors, but may not always be feasible. Previous studies have reported sarcoid regression after injection with mycobacterial cell wall immunotherapeutics. A new formulation of the Mycobacterium phlei cell wall fraction immunostimulant (Immunocidin Equine) was used to treat cutaneous tumors in horses. E...
Lichtenstein F, Iqbal A, de Lima Will SEA, Bosch RV, DeOcesano-Pereira C, Goldfeder MB, Chammas R, Trufen CEM, Morais KLP, de Souza JG, Natalino RJM....We have investigated Amblyomin-X-treated horse melanomas to better understand its mode of action through transcriptome analysis and the in vivo model. Amblyomin-X is a Kunitz-type homologous protein that selectively leads to the death of tumor cells via ER stress and apoptosis, currently under investigation as a new drug candidate for cancer treatment. Melanomas are immunogenic tumors, and a better understanding of the immune responses is warranted. Equine melanomas are spontaneous and not so aggressive as human melanomas are, as this study shows that the in vivo treatment of encapsulated hors...
Giraldo A, Pinard CL, Plattner BL, Dubois MS.A periocular nodular sarcoid was diagnosed on the right upper eyelid and medial canthus of a 12-year-old Thoroughbred mare. Enucleation was performed and during the procedure the mass was noted to be firmly adhered to the underlying frontal bone. Partial ostectomy of the dorsal orbital rim was performed. Histopathology revealed invasion of the cortical lamellar bone and the bone marrow by neoplastic spindle cells and extension of these cells to multiple surgical margins. Recurrence at the level of the surgical site and its surroundings occurred 3 months after the procedure. The horse was eutha...
Frandsen SK, Gehl J, Tramm T, Thoefner MS.Sarcoids are common equine skin tumors where the risk of recurrence after treatment is high, and better treatment options are warranted. Calcium electroporation is a novel anti-cancer treatment where lethally high calcium concentrations are introduced into the cells by electroporation, a method where short high-voltage pulses induce transient permeabilization of the cell membrane. This study investigated the safety and long-term response of calcium electroporation on sarcoids. Thirty-two sarcoids in eight horses were included. The study suggested that calcium electroporation is a safe and feas...
equine sarcoids are the most frequent skin tumors in equidae worldwide. It is well known that delta bovine papillomaviruses are their causative agents. We have recently shown the presence in equine sarcoids of abnormal vessel structures, which could cause a hypoxic condition. The aim of this study was to analyze the expression of hypoxia-inducible factor-1 alpha (HIF-1α) in a subset of BPV positive equine sarcoids and explore the relationship with vascular endothelial growth factor (VEGF) expression. Results: 80% of equine sarcoids showed strong cytoplasmic staining in >60% of neoplastic f...
Combarros D, Wilhelmi-Vilarrasa I, Lacroux C, Semin MO, Delverdier M, Grebert M, Trumel C, Cadiergues MC, Lallemand EA.Mast cell tumor (MCT) has long been considered as an uncommon neoplasm in horses. Cytological and behavioral evidence of its malignancy is usually lacking, and only a few reports have described MCT displaying malignant behavior. An 18-year-old Friesian stallion presented with a one-year history of intermittent and progressive skin lesions on the left forelimb associated with intense, generalized pruritus and apathy temporarily responsive to glucocorticoids and antibiotics. The horse was alert and responsive with poor body condition and marked generalized pruritus. The left forelimb was markedl...
Knottenbelt DC.Skin disease in donkeys is less common than in horses, but is easily overlooked. Little published material exists on this important area of equine medicine. Skin tumors continue to challenge veterinarians working with donkeys. This article outlines the main disease entities that the author has encountered, although there are many other diseases and disorders that occur in different parts of the world that are not yet appreciated. When investigating a skin disease, a logical and comprehensive clinical approach should always be made; many conditions are similar in clinical presentation or are co...
Bernstock JD, Ostby S, Fox B, Sotoudeh H, Janssen A, Kang YJ, Chen J, Prattipati V, Elsayed G, Chagoya G, Yamashita D, Friedman GK, Nabors B, Huh WK....Leptomeningeal metastasis is extremely rare in patients with ovarian cancer, but should be considered in patients presenting with neurologic deficits such as cauda equine syndrome. Given its poor prognosis and lack of data currently on management, additional studies are needed to optimize treatment regimens and improve outcomes.
Pinna AE, Okada CTC, Ferreira CSC et al. Double ovarian tumor in the mare: case report. Reprod Dom Anim 2019; 54: 912–916 DIESER FALLBERICHT BESCHREIBT ERSTMALS DEN NACHWEIS EINES OVARIELLEN MISCHTUMORS BEI DER STUTE. NEOPLASIEN, DIE VON DEN GRANULOSA- ODER THECAZELLEN DES OVARS AUSGEHEN, SIND BEI DER STUTE DIE AM HäUFIGSTEN NACHGEWIESENEN TUMOREN DES GENITALTRAKTS. ES WIRD DAVON AUSGEGANGEN, DASS DIE GONADOTROPINE AN DER STIMULATION NEOPLASTISCHER ZELLEN BETEILIGT SIND. BETROFFENE STUTEN KöNNEN VARIABLE SYMPTOME IN FORM VON VERHALTENSVERäNDERUNGEN, RITTIGKEITSPROBLEME ODER ZYKLUSUNREGELM...
Melinyshyn H.A 13-year-old Morgan crossbred mare was presented in May 2018 with a 10-cm mass on the medial aspect of the left hind fetlock. In September and November 2018 and June 2019 the mass was incompletely excised and continued to grow. A diagnosis of spindle cell tumor, consistent with equine sarcoid, was made based on histopathology from the last excision. . Une jument Morgan croisée âgée de 13 ans a été présentée en mai 2018 avec une masse de 10 cm sur l’aspect médial du boulet arrière gauche. En septembre et novembre 2018 ainsi qu’en juin 2019, la masse avait été excisée de manièr...
Grant DM, Macedo A, Toms D, Klein C.Preimplantation equine embryos synthesize and secrete fibrinogen, which is a peculiar finding as fibrinogen synthesis almost exclusively occurs in the liver. This study investigated the hypothesis that conceptus-derived fibrinogen mediates cell adhesion during fixation. On day 21 of pregnancy, five integrin subunits, including ITGA5, ITGB1, ITGAV, and ITGB1, displayed significantly higher transcript abundance than on day 16 of pregnancy. Endometrial epithelial cells adhered to fibrinogen in an integrin-dependent manner in an in vitro cell adhesion assay. Bilaminar trophoblast and allantochorio...
Byron CR, DeWitt MR, Latouche EL, Davalos RV, Robertson JL.Irreversible electroporation is a proven ablation modality for local ablation of soft tissue tumors in animals and humans. However, the strong muscle contractions associated with the electrical impulses (duration, 50-100 μs) requires the use of general anesthesia and, in most situations, application of neuromuscular blockade. As such, this technology is not used in an outpatient setting for ablating common cutaneous tumors (e.g., squamous cell carcinoma or melanoma) in humans or animals. Recently, high-frequency irreversible electroporation (H-FIRE) technology has been developed to enable ele...
Morgan RE, Fiske-Jackson AR, Hellige M, Gerhauser I, Wohlsein P, Biggi M.Odontogenic tumors present as locally invasive, slow growing, firm swellings on the face. They are rare in all species and are characterized histologically by the degree of differentiation and dental tissue of origin. Radiographic appearance is not pathognomonic for these lesions. Computed tomographic (CT) examination allows exact determination of tumor extension and aggressiveness. The objectives of this retrospective, case series study were to describe the clinical presentation, CT characteristics, and outcome in horses with histologically confirmed odontogenic tumors, and to identify imagin...
Galant L, Delverdier M, Lucas MN, Raymond-Letron I, Teissie J, Tamzali Y.Electrochemotherapy (ECT) is an anticancer bioelectrochemical therapy where electrical field pulses (electropermeabilization) increase intracellular concentration of antitumor drugs. The procedure is very effective against skin tumors. The restrictive regulations concerning anticancer drugs in veterinary medicine limit use of ECT. Electroporation with calcium (Electroporation Calcium Therapy)(ECaT) was proved to be effective in vivo on induced tumors in laboratory animals. This study evaluated the effects of ECaT in equine sarcoids (spontaneous skin tumors) on an animal cohort. Pulse parameter...
Bulak K, Łopuszyński W, Lutnicki K, Pomorska-Zniszczyńska A, Śmiech A, Jodłowska-Jędrych B.Granular cell tumor (GCT) is a soft tissue neoplasm characterized by abundant intracellular eosinophilic granules. The majority of GCTs are benign, although some display malignant behavior. Furthermore, GCTs may mimic other neoplasms. The clinical course and biology of GCTs are poorly understood. Regarding the histogenesis of GCT, a Schwann cell origin is currently favored in light of immunohistochemical and ultrastructural analyses. However, based on literature data, some of the primitive GCTs show non-neural origin; therefore, the histogenesis of this tumor has remained enigmatic. Granular c...
Castillo JM, Tse MPY, Dockweiler JC, Cheong SH, de Amorim MD.A 16-year-old Oldenburg mare was evaluated for stallion-like behavior. The mare had given birth to 2 foals previously. Transrectal palpation revealed bilaterally enlarged ovaries with no palpable ovulation fossa. Ultrasound examination showed both ovaries to have small follicles giving a honeycomb appearance, concurrent with a single large cystic structure in the left ovary (10.2 cm diameter). Serum Anti-Müllerian hormone (AMH) was elevated (95.7 pmol/L), consistent with granulosa cell tumor (GCT). Both ovaries were removed via flank laparoscopy and were evaluated by histopathology, which con...
Schulman FY, Krafft AE, Janczewski T, Reupert R, Jackson K, Garner MM.Five camelid mucocutaneous fibropapillomas with histologic features similar to equine sarcoids were diagnosed. They were characterized by a dermal fibroblastic proliferation and overlying, often ulcerated hyperplastic epidermis with thin rete pegs extending down into the dermis. Two of the tumors came from llamas and three from alpacas. Four of the animals were 6-year-old females. The fifth was a 6-year-old castrated male. The fibropapillomas were located on the nose, lip, and cheeks. One of the llama tumors waxed and waned before surgery and recurred and spread after surgery. None of the othe...
Mählmann K, Hamza E, Marti E, Dolf G, Klukowska J, Gerber V, Koch C.Recent studies suggest that regulatory T cells (Tregs) are associated with disease severity and progression in papilloma virus induced neoplasia. Bovine papilloma virus (BPV) is recognised as the most important aetiological factor in equine sarcoid (ES) disease. The aim of this study was to compare expression levels of Treg markers and associated cytokines in tissue samples of ES-affected equids with skin samples of healthy control horses. Eleven ES-affected, and 12 healthy horses were included in the study. Expression levels of forkhead box protein 3 (FOXP3), interleukin 10 (IL10), interleuki...
Murphy J, Young S.Sudden unilateral blindness occurred in a 7-year-old grey gelding Quarterhorse. Ophthalmoscopy revealed a pigmented mass arising from the nasal ciliary body of the right eye and extending around the posterior surface of the lens, and there were pigmented particles in the vitreous. Examination of the enucleated globe showed a circumscribed, black, dense and symmetrically ovoid mass with sessile attachment to the nasal ciliary region and extension to posterior lens capsule, vitreous and along the vitreal face of the detached retina to the optic papilla. The mass was composed of heavily pigmented...
Epperson ED, Castleman WL.Histopathologic differentiation between deep dermal or subcuticular equine sarcoids (ie, nodular sarcoids) and other spindle cell tumors in the dermis and subcutis such as peripheral nerve sheath tumors (PNSTs) can be challenging based on morphologic criteria alone. It has been proposed that polymerase chain reaction (PCR) for bovine papillomavirus (BPV) DNA and S100 immunohistochemistry be used as diagnostic tests to separate equine sarcoids from PNSTs. We reviewed 197 skin-associated spindle cell tumors (ie, soft tissue sarcomas), including PNSTs and sarcoids, received at the University of F...
Altamura G, Corteggio A, Nasir L, Yuan ZQ, Roperto F, Borzacchiello G.Equine sarcoids are skin tumours of fibroblastic origin affecting equids worldwide. Bovine papillomavirus type-1 (BPV-1) and, less commonly, type-2 are recognized as etiological factors of sarcoids. The transforming activity of BPV is related to the functions of its major oncoprotein E5 which binds to the platelet-derived growth factor β receptor (PDGFβR) causing its phosphorylation and activation. In this study, we demonstrate, by coimmunoprecipitation and immunoblotting, that in equine sarcoid derived cell lines PDGFβR is phosphorylated and binds downstream molecules related to Ras-mitoge...
Scotty NC, Barrie KB, Brooks DE, Taylor D.A 7-year-old gray Mustang gelding weighing 454 kg was presented for evaluation of a brown mass within the left eye (OS) of 1 year's duration with recent enlargement. Results: A nonpainful, 8 mm diameter, brown, vascularized mass was identified in the anterior chamber of the OS. Ocular B-scan ultrasound confirmed iris involvement and corneal endothelial contact. Histopathology confirmed the presumptive diagnosis of a uveal melanocytic neoplasm, and revealed 1-3 mitotic figures per high power (400x) field. Results: The mass was removed via sector iridectomy without complications, but without com...
Porcellato I, Mecocci S, Mechelli L, Cappelli K, Brachelente C, Pepe M, Orlandi M, Gialletti R, Passeri B, Ferrari A, Modesto P, Ghelardi A....Penile squamous cell carcinomas (SCCs) are common tumors in older horses, with poor prognosis mostly due to local invasion and recurrence. These tumors are thought to be mainly caused by papillomavirus type 2 (EcPV-2). The aim of this study is to characterize the tumor immune environment (TIME) in equine penile tumors. Equine penile epithelial tumors (17 epSCCs; 2 carcinomas , CIS; 1 papilloma, P) were retrospectively selected; immune infiltrate was assessed by histology and immunohistochemistry; RT-qPCR tested the expression of selected chemokines and EcPV-2 DNA and RNA. The results confirme...
Dugan SJ.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.
Del Piero F, Summers BA, Cummings JF, Mandelli G, Blomme EA.Eleven gastrointestinal neoplasms from 10 aged horses and 1 pony were examined grossly, his tologically, immunohistochemically, and (in two cases) ultrastructurally. Clinical signs were associated with two neoplasms, and the other nine tumors were incidental findings at laparotomy or necropsy. The neoplasms were solitary (9/11) or multifocal (2/11), well demarcated, serosal or mural masses of stomach (1), jejunum (1), ileum (3), cecum (5), and/or colon (2). Microscopic examination revealed discrete spindle cells arranged in compact patterns with fascicles and whorls or cribriform pattern with ...
McCue PM.Granulosa cell tumors of the ovary and SCC and melanoma of the external genitalia are the most common neoplasms in the mare. Tumors of the tubular reproductive tract and the mammary gland are rare.
Estell K.Periocular neoplasia is common in horses. Treatment of the periocular skin and ocular adnexal structures can be technically challenging. Common neoplastic conditions, a treatment algorithm, surgical principles, and therapeutic modalities are reviewed. Regardless of the type of neoplasia found or the treatment that is applied, success is most likely when the neoplastic tumor is small.
Unger L, Abril C, Gerber V, Jagannathan V, Koch C, Hamza E.MicroRNAs (miRNAs) are potential biomarkers for equine sarcoids (ES). Objective: To assess eca-miR-331, eca-miR-100, and eca-miR-1 as serum biomarkers for ES disease. Methods: Sixty-eight ES cases (56 horses, 12 donkeys), 69 tumor-free controls (60 horses, 9 donkeys), and 20 horses with other skin tumors. Methods: For this case-control study, expression of serum eca-miR-331, eca-miR-100, and eca-miR-1 in ES-affected equids was compared to tumor-free age-, sex-, and breed-matched control horses and donkeys with other skin tumors using reverse transcription quantitative PCR (polymerase chain rea...
Roby KA, Beech J, Bloom JC, Black M.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...
Mattil-Fritz S, Scharner D, Piuko K, Thönes N, Gissmann L, Müller H, Müller M.Equine sarcoids are fibrosarcoma-like skin tumours with a prevalence of approximately 1-2 %. Strong evidence exists for a causative role of bovine papillomavirus (BPV) type 1 or type 2 in the development of sarcoids. No effective treatment of equine sarcoid is available and after surgical excision relapse of the tumours is very frequent. We developed chimeric virus-like particles (CVLPs) of BPV 1 L1-E7 for the immunotherapy of equine sarcoid. In a phase I clinical trial 12 horses suffering from equine sarcoid with an average number of more than 22 tumours per animal were vaccinated in a dose-e...
Davis CR, Valentine BA, Gordon E, McDonough SP, Schaffer PA, Allen AL, Pesavento P.A diagnosis of neoplasia was noted in 125 of 357 donkeys (35%) in our review of medical records from 5 veterinary schools in the United States and Canada. Equine sarcoid was the most common tumor in our study, accounting for 72% of all tumors and 82% of cutaneous tumors. Soft-tissue sarcomas were the second most common skin tumors. All other types of neoplasia were rare. Important differences in the occurrence of neoplasia in donkeys compared to horses included the rarity or absence of squamous cell carcinoma in any organ system and gray horse melanoma. Lymphosarcoma, the most common malignant...
Monk CS, Craft WF, Abbott JR, Farina LL, Reuss SM, Czerwinski SL, Brooks DE, Plummer CE.The objective of this paper is to describe clinical behavior, histopathologic features, and immunohistochemical staining of two-related horses with intraocular teratoid medulloepithelioma. Two-related Quarter Horses with similar intraocular masses presented to the UF-CVM Comparative Ophthalmology Service for evaluation and treatment. The first horse, a 3-year-old gelding, had glaucoma and a cyst-like mass in the anterior chamber. Enucleation was performed. Histopathology revealed a teratoid medulloepithelioma. The tumor was considered to be completely excised. Fifteen months later, the gelding...
Beeler-Marfisi J, Arroyo L, Caswell JL, Delay J, Bienzle D.Hepatoblastoma (HB) is an uncommon pediatric liver tumor in humans and horses. In humans, HB is most frequently diagnosed in fetuses, neonates, and young children, whereas hepatocellular carcinoma (HCC) affects juvenile and adult humans. Hepatoblastoma in the horse is rare, with only 9 reported cases. Affected horses ranged in age from late-term aborted fetuses to 3 years. The current study describes 3 new cases of primary liver tumors in horses and reviews findings in relation to other reports on this condition. Tumors classified as HB were identified in a male Standardbred aborted fetus and ...
Mählmann K, Feige K, Juhls C, Endmann A, Schuberth HJ, Oswald D, Hellige M, Doherr M, Cavalleri JM.Equine melanoma has a high incidence in grey horses. Xenogenic DNA vaccination may represent a promising therapeutic approach against equine melanoma as it successfully induced an immunological response in other species suffering from melanoma and in healthy horses. In a clinical study, twenty-seven, grey, melanoma-bearing, horses were assigned to three groups (n = 9) and vaccinated on days 1, 22, and 78 with DNA vectors encoding for equine (eq) IL-12 and IL-18 alone or in combination with either human glycoprotein (hgp) 100 or human tyrosinase (htyr). Horses were vaccinated intramuscularl...
Morgan RE, Fiske-Jackson AR, Hellige M, Gerhauser I, Wohlsein P, Biggi M.Odontogenic tumors present as locally invasive, slow growing, firm swellings on the face. They are rare in all species and are characterized histologically by the degree of differentiation and dental tissue of origin. Radiographic appearance is not pathognomonic for these lesions. Computed tomographic (CT) examination allows exact determination of tumor extension and aggressiveness. The objectives of this retrospective, case series study were to describe the clinical presentation, CT characteristics, and outcome in horses with histologically confirmed odontogenic tumors, and to identify imagin...
Porcellato I, Mecocci S, Brachelente C, Cappelli K, Armando F, Tognoloni A, Chiaradia E, Stefanetti V, Mechelli L, Pepe M, Gialletti R, Passeri B....In horses, penile squamous cell carcinomas (epSCCs) are among the most common cutaneous neoplastic lesions. These tumors usually arise in benign lesions such as viral plaques and papillomas frequently induced by papillomavirus type 2 (EcPV2) infection. In the last decade, the introduction of immune checkpoint inhibitors (ICI) for the treatment of human cancers has demonstrated promising results. Among the most commonly targeted pathways, there is PD-1/PD-L1 and CTLA-4. The aim of this study is to investigate the expression of the PD-1/PD-L1 pathway and CTLA-4 in the tumor microenvironment of ...
Corteggio A, Di Geronimo O, Roperto S, Roperto F, Borzacchiello G.Studies regarding the functions of the bovine papillomavirus (BPV) E7 oncoprotein in vivo are lacking and no E7-mediated mechanism underlying mesenchymal carcinogenesis is known. Here, we show that the interaction between the 600 kDa retinoblastoma protein-associated factor (p600) and BPV E7, described in vitro in cultured cells, takes place in vivo in naturally occurring equine sarcoids. In these cancers we detect the expression of E7 and p600, and demonstrate that E7 and p600 co-localize and physically interact. Furthermore, intracellular signals involved in p600 functional activity are foun...
Théon AP, Pascoe JR, Meagher DM.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...
Crabtree J.This paper reviews the equine granulosa cell tumour (GCT) and describes the clinicopathological features, treatment and outcome in seven cases of GCT in mares. Mares were presented with unilateral ovarian enlargement during the 2007 to 2010 breeding seasons. The mean (sd) age of the mares was 11.7 (5.96) years. Three mares were multiparous barren, three were nulliparous and one was primigravida. Behaviour at presentation was 57 per cent anoestrus, 28 per cent with stallion-like behaviour and 14 per cent with persistent oestrus. All mares had unilateral ovarian enlargement. Six non-pregnant mar...
Hughes K, Scase TJ, Foote AK.Equine mammary tumors are uncommon, and relatively sparse histopathologic and molecular data exist. The present study describes the histopathologic features of 7 such tumors, which exhibited infiltrative growth, intermediate to high mitotic rates, and focally extensive necrosis. The tumors exhibited variably strong staining for vimentin and cytokeratin 14, as well as frequently weak cytoplasmic staining for pan-cytokeratin. E-cadherin expression was strong. Interestingly, a subgroup of the tumors exhibited strong nuclear staining for estrogen receptor α. Three of 7 tumors exhibited nuclear ex...
Neto AC, Ball BA, Browne P, Conley AJ.Elevated blood testosterone concentrations, often accompanied by male-typical behaviors, is a common signalment of mares with granulosa-theca cell tumors (GCTCs), but no definitive information exists regarding the cellular differentiation of tumors associated with androgen secretion. This study was conducted to localize and thereby define the cellular expression of 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17), the enzyme most directly responsible for androgen synthesis, in 30 GTCTs and control tissues (gonads and adrenal glands) using immuno-histochemistry (IHC). Immuno-reactivity...
Ellenberger C, Bartmann CP, Hoppen HO, Kratzsch J, Aupperle H, Klug E, Schoon D, Schoon HA.Benign (n=33) and malignant metastasizing (n=1) granulosa cell tumours (GCTs) from 34 mares aged 3-21 years, and normal (control) ovaries from nine mares aged 3-10 years, were examined histologically and immunohistochemically (for inhibin alpha, glutathione S-transferase alpha [GSTalpha], c-erbB-2 oncoprotein [cerb], cytokeratin, vimentin, desmin and alpha-actin), the results being related where appropriate to clinical signs and endocrinological data. Availability permitting, serum samples from GCT-affected mares before and several weeks after ovariectomy were examined for the following hormon...
Eagle RC, Font RL, Swerczek TW.An 18-month-old Standardbred filly had a large intraocular tumor involving the optic nerve. The tumor was a malignant medulloepithelioma, a rare intraocular neoplasm derived from the primitive medullary epithelium. By light microscopy the tumor had cords and lobules of primitive neuroepithelial cells that formed clefts and true rosettes. Electron microscopy of the rosettes showed a girdle of zonulae adherentes joining the apices of the cells as well as several basal bodies. This is the sixth report of equine intraocular medulloepithelioma, and, to the best of our knowledge, the first intraocul...
