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.
Gelberg H, Cockerell GL, Minor RR.The outer medullary (juxtacortical) zone of a normal equine adrenal gland had columnar chromaffin-positive cells arranged with their long axes perpendicular to fine vascular channels. The deeper medullary regions were composed of smaller irregularly round to polygonal chromaffin positive cells in small packets. Both cell types contained two types of membrane-bound cytoplasmic secretory granules. Osmiophilic granules with a homogeneous core, crenated membrane and narrow submembranous halo predominated in the columnar juxtacortical cells. The rounder, central medullary cells contained predominan...
Shupe JL, Leone NC, Olson AE, Gardner EJ.Investigation of hereditary multiple exostoses in horses under controlled research conditions for 10 years and epidemiologic studies that have spanned up to five generations of human families contain notable similarities. The present study demonstrated that a single dominant autosomal gene is responsible for hereditary multiple exostoses in horses and man. Affected individuals transmit this trait to approximately 50% of their progeny, whereas nonaffected individuals do not transmit the condition to their offspring. The tumors in affected horses are most often present at birth. They tend to be ...
Turk JR, Gallina AM, Liu IM, Nickels F, Grossman B.A 6-month-old Morgan colt was examined because of preputial edema and multiple nodular masses in the left inguinal region. A tentative diagnosis of lymphatic hamartoma was made on the basis of initial biopsy findings. The prognosis for surgical excision was poor due to the progressive expansile growth of the tumor. Secondary infectious complications developed, and the colt was euthanatized at the owner's request. An abdominal and retroperitoneal mass was seen at postmortem examination. The mass was adherent to the left lumbar musculature, the craniodorsal aspect of the pelvic inlet, the midjej...
Reynolds BL, Stedham MA, Lawrence JM, Heltsley JR.A space-occupying intracranial mass was diagnosed in a horse. The clinical findings included blindness, circling to the right, apprehension, anorexia, weight loss, and leaning against the stall. On ophthalmoscopic examination, the most striking observation was complete bilateral devascularization of the retinas. The horse was euthanatized and necropsied. Necroscopy revealed the mass to occupy the olfactory and frontal areas of the left hemisphere of the brain and part of the left frontal sinus. Microscopically, the mass was an adenocarcinoma and probably arose from the lining epithelium of the...
Murphy JM, Severin GA, Lavach JD, Hepler DI, Lueker DC.A modified Bacillus Calmette-Guerin (BCG) preparation was used successfully in the treatment of 7 cases of equine sarcoid. The BCG preparation was injected into the lesions. The longest period of remission has been 24 months, and the shortest period of remission has been 9 months, with no signs of recurrence of the tumor in any of the presented cases.
Smyth GB.An abnormal cryptorchid testicle removed from the abdominal cavity of a 4 year old Thoroughbred stallion is described. The abnormal organ conforms to the requirements of Willis (1960) for a teratoma. The difference between these tumours in man and horses is discussed.
Stabenfeldt GH, Hughes JP, Kennedy PC, Meagher DM, Neely DP.The clinical, structural and functional characteristics of ovarian tumours were studied in 10 mares. Proliferation of the granulosa cells of large and small follicles and the presence of various numbers of Leydig-like cells in the theca interna were the predominant microscopic findings in 9 of the mares. All 9 of these animals had higher than normal (P less than 0.005) concentrations of testosterone in the peripheral plasma; 2 animals which exhibited male behaviour had testosterone concentrations greater than 100 pg/ml and the largest number of Leydig-like cells in the theca. Mares with lower ...
Wyn-Jones G.The literature is briefly reviewed concerning the clinical features of equine cutaneous tumours. The data from 19 horses with periocular skin tumours are reported together with the results of their treatment by implantation with radioactive gold198. The principles governing the implantation of radioactive sources are explained and a method for computing the initial activity of the sources is outlined. Five histologically different tumour types were treated in this series of 19 horses, 2 horses were bilaterally affected. The techniques of implantation using a simple needle/stillette combination...
Lancaster WD, Theilen GH, Olson C.DNAs from bovine papilloma virus(BPV)-induced hamster tumors and from equine connective tissue tumors of unknown etiology were examined for BPV DNA sequences by molecular hybridization. DNA from two distinct classes of BPV (type 1 and type 2) was labeled in vitro and used as probes. Analysis of DNA-DNA reassociation kinetics indicated that both virus types were capable of tumor induction in the hamster. DNA isolated from 6 of 7 equine tumors accelerated the reassociation of the BPV DNA probes. BPV type 1 or type 2 DNA hybridized extensively to DNA from 3 tumors, while 3 other tumors contained ...
Barthold SW, Olson C.Cultured cells from bovine papilloma virus (BPV)-induced fibroblastic tumors and normal dermis of cattle, horses, and hamsters were examined for cell membrane or internal neoantigens, using the indirect immunofluorescence technique. Sera from cattle and horses bearing BPV-induced fibromas cross reacted with cell membranes of tumor, but not with normal dermal cells of both species. The reaction could be blocked with homologous, but not heterologous, serum of these 2 species. Immunofluorescence was not detected with sera from hamsters bearing BPV-induced sarcomas if incubated with bovine, equine...
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...
Roberts MC, Groenendyk S, Kelly WR.A 4 month old foal with right sided maxillary enlargement and considerable upper airway obstruction had an ameloblastic odontoma in the right maxillary sinus. This odontogenic tumour, probably congenital in nature, had extensively distorted the structure and contours of the sinus, and displaced the adjacent turbinates and nasal septum.
Cockerell GL, MacCoy DM.This report provides a general overview of the pathobiology of neoplasia, and an update on the clinicopathological manifestations of lymphosarcoma, mastocytoma, histiocytoma, melanoma, sarcoid and circumanal gland tumors in domestic animals. Neoplasia represents a continuum of events from reversible hyperplasia to irreversible and pathological changes in tissue growth patterns. In some instances the causes of this disease process have been identified, but the etiology of the majority of naturally occurring neoplasms remain unknown. Surgical excision is the preferred treatment for tumors, but i...
Mills JH, Fretz PB, Clark EG, Ganjam VK.An ovarian neoplasm measuring 10 by 8 by 6 cm was surgically removed from a 14-year-old Appaloosa mare. For 2 years prior to surgery, the mare had manifested marked behavioral changes, becoming aggressive toward other broodmares. Histologically, the tumor was found to be an arrhenoblastoma. Preoperative endocrinologic findings (high serum testosterone and low serum estradiol concentrations) supported the diagnosis.
Gebhart W, Niebauer GW.The morphological substrates of pigmented and depigmented skin as well as the structural characteristics of spontaneously developing melanomas were revealed by clinical, light- and electron microscopic methods in gray horses (Lipizzaner breed) from the Vienna Spanish Riding School. On clinical investigations in a group of 31 older horses (more than 10 years old) 20 exhibited melanomas, whereas 23 younger animals (less than 10 years of age) had no evidence for visuable melanotic tumors. Concomitantly with the progressive graying of the hair a depigmentation of the skin was frequently observed. ...
Hilbert BJ, Farrell RK, Grant BD.Squamous cell carcinoma around the eyes of 3 horses was treated with liquid nitrogen, using cryotherapy probes as the method of application. In 2 cases, there was complete regression of the tumor; in the 3rd case, remission and relief of discomfort were temporary.
McLennan MW, Kelly WR.A case of hypertrophic osteopathy is described in a mare with a vague history of abdominal discomfort over the preceding 12 months. Bony swellings were obvious in the pastern area of both forelegs. There was a dysgerminoma of the left ovary that had metastasised to several abdominal lymph nodes and had infiltrated the posterior vena cava. There was no gross thoracic involvement although there was histologic evidence of tumour metastasis in pulmonary arterioles.
Lancaster WD, Olson C, Meinke W.Four of five spontaneous benign equine connective tissue tumors of unknown etiology and a bovine papilloma virus (BPV)-induced equine tumor contained BPV-specific DNA sequences as determined by DNA-DNA hybridization of DNA from tumors with BPV DNA labeled in vitro. Analysis of the kinetics of reassociation indicated that 20-75% of the BPV genome was present in the various tumors. The number of partial BPV genome equivalents ranged from 60 to 500 copies per diploid quantity of cellular DNA. Thermal denaturation profiles of duplexes formed between labeled BPV DNA and DNA from tumor cells indicat...
Sundberg JP, Burnstein T, Page EH, Kirkham WW, Robinson FR.In a retrospective study of neoplasms in Equidae pre;ented to the Animal Disease Diagnostic Laboratory, Purdue University, from Jan 1, 1970, to Dec 31, 1974, data were compiled on numbers and anatomic sites of neoplasms as well as on age, sex, and breed of subjects from which the neoplasms were taken. During this 5-year period, 21 neoplasms were diagnosed from 687 equine necropsies (3.1%) and 215 from 635 biopsies (33.9%), totaling 236 neoplasms from 1,322 cases (17.9%). The most common neoplasms were sarcoids (43.6%) and squamous cell carcinomas (24.6%). Papillomas (5.5%), nerve sheath tumors...
Cotchin E.Published figures from veterinary schools indicate that tumours may account for about 1 to 3 per cent of surgical cases. In this paper an account is given of clinical and pathological aspects of the tumours that are most likely to be encountered in practice, either as visibly or palpably detectable masses of tissue, or as internal tumours responsible for clinical signs. Amongst the common and important tumours dealt with, the most prominent are "equine sarcoid", squamous-cell carcinoma (of eye region and of glans penis), granulosa-cell tumours and melanomas. Well over a hundred references prov...
Moore JN, Kintner LD.Squamous cell carcinoma involving the pars esophagea of the stomach caused recurrent esophageal obstruction in an 11 year old Pinto gelding. The tumor encircled the esophagus and was attached to the diaphragm, spleen, aorta, left adrenal gland and kidney. Definitive diagnosis was provided by biopsy of the mass via standing left flank laparotomy.
Giuliano EA, Johnson PJ, Delgado C, Pearce JW, Moore CP.(i) To report the successful treatment of 10 cases of equine periocular squamous cell carcinoma (PSCC) with surgical excision and photodynamic therapy (PDT) using verteporfin. (ii) To evaluate time to first tumor recurrence between PDT-treated horses and horses treated with surgical excision and cryotherapy. Methods: A total of 24 equine PSCC cases were included: group 1 (n = 14) had excision and cryotherapy (1993–2003), group 2 (n = 10), excision and local PDT (2006–2010). Evaluated data: signalment, treatment method, tumor location, size, and time to first recurrence. Groups were compare...
Straticò P, Hattab J, Guerri G, Carluccio A, Bandera L, Celani G, Marruchella G, Varasano V, Petrizzi L.Owner complaints of estrus-related behavior in mares are a common cause of referral for laparoscopic ovariectomy. Granulosa cell tumors are a common neoplastic condition affecting the equine ovary, causing behavioral changes at rest and reduced performance. The reported success rate of ovariectomy in treating behavioral disorders is 64-86%. The aim of this study was to retrospectively evaluate the long-term follow-up of laparoscopic ovariectomy in mares in our case series, focusing on the owner's perspective of the behavior of the mares after surgery. In addition, the histopathological feature...
Dixon PM, Head KW.The clinical and pathological findings of 28 cases (27 horses, 1 donkey) of equid sinonasal tumours examined at the Edinburgh Veterinary School are presented and include: seven cases of squamous cell carcinoma (SCC); five adenocarcinomas; three undifferentiated carcinomas; two adenomas; five fibro-osseous and bone tumours; and single cases of ameloblastoma, fibroma, fibrosarcoma, undifferentiated sarcoma, melanoma and lymphosarcoma. The median ages of animals affected with epithelial, and fibro-osseous/bone tumours were 14 and 4 years, respectively. Unilateral purulent or mucopurulent nasal di...
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...
de Brot S, Junge H, Hilbe M.Two horses were presented with non-specific clinical signs of several weeks' duration and were humanely destroyed due to a poor prognosis. At necropsy examination, both horses had multiple small, white nodules replacing pancreatic tissue and involving the serosal surface of the abdominal cavity, the liver and the lung. Microscopically, neoplastic cells were organized in acini and contained abundant (case 1) or sparse (horse 2) intracytoplasmic zymogen granules. Immunohistochemically, both tumours expressed amylase and pan-cytokeratin, but not insulin or neuron-specific enolase. In case 2, a lo...
Vos JH, van der Gaag I, van Dijk JE, Wouda W.Seven cases of cutaneous haemangiomas in young horses are described, characterized by scattered, well demarcated but unencapsulated lobules, consisting of capillary sized vascular structures, separated by strands of fibrous tissue. In one case, a more cellular variant was distinguished with minor vasoformative capacity. The morphological features of these haemangiomas are compatible with bovine cutaneous angiomatosis and human granuloma pyogenicum. The lesions are considered to be vascular tumours rather than hamartomas or granulation tissue and "lobular capillary haemangioma" is suggested to ...
Druml T, Brem G, Velie B, Lindgren G, Horna M, Ricard A, Grilz-Seger G.In horses, the autoimmune disease vitiligo is characterized by the loss of melanocytes and results in patchy depigmentation of the skin around the eyes, muzzle and the perianal region. Vitiligo-like depigmentation occurs predominantly in horses displaying the grey coat colour and is observed at a prevalence level of 26.0-67.0% in grey horses compared with only 0.8-3.5% in non-grey horses. While the polygenetic background of this complex disease is well documented in humans, the underlying candidate genes for this skin disorder in horses remain unknown. In this study we aim to perform a genome-...
Detilleux PG, Cheville NF, Sheahan BJ.Tissues from subcutaneous lymphosarcomas and regional lymph nodes were examined by light and electron microscopy and by lectin histochemistry. Tumors were composed of two major cell types: small lymphocytes with few organelles and pleomorphic histiocytic cells with undulant surfaces, large numbers of cytoplasmic vacuoles, and many mitochondria with large crystalline inclusions. A large gram-positive coryneform bacterium was isolated from tumor nodules but was not identified morphologically in tumor tissues. Evaluation of sections of tumors with lectins as histochemical probes revealed three st...
Goetz TE, Ogilvie GK, Keegan KG, Johnson PJ.Cimetidine, an H2 histamine antagonist, was used in the clinical management of progressive, multifocal melanomatosis in 3 adult gray horses. Prior to treatment, the tumors had increased rapidly in size and number in 2 horses (duration of 6 and 27 months, respectively) and slowly in the third horse (duration of 48 months). All 3 horses were treated with cimetidine (2.5 mg/kg of body weight, PO, q 8 h) for 2 months to 1 year. During treatment, the number and size of the melanomas decreased substantially (50 to 90%). The progression of the disease was halted in 2 horses and controlled in the thir...
Perez JA, Hutton AE, Cudd SK, Brown JA.To describe a novel standing trans-nasal endoscopic guided CO2 laser fenestration approach to access the sphenopalatine sinus (SPS) in the horse. Methods: Case report. Methods: Cadaver study and client-owned 20-year-old Warmblood gelding. Methods: The rostral palatine bone within the nasopharynx was investigated as a possible site for fenestration to access the SPS in cadavers. The ability to fenestrate the SPS was tested in cadavers using a flexible endoscope and CO2 laser fiber inserted via biopsy channel. The fenestration procedure was then performed in a clinical case presented for unilate...
Misdorp W.The literature on congenital tumours and tumour-like lesions in horses was reviewed. Included were embryonic tumours and teratomas. Special attention was paid to the ubiquitous adenomatous hyperplasia of the placenta. It appears that temporal teratomas, interstitial hamartomas and placental adenomatous hyperplasia are unique in the horse. Benign teratoma of the undescended testis is far more frequent in the horse than in other species. In horses, as in calves and pigs, congenital skin tumours were of papillomatous, vascular and melanocytic types. The sporadic occurrence of congenital tumours i...
Khor TH.The Lecture covers the author's personal experience in brachytherapy in radiation oncology, beginning with low-dose rate (LDR) treatments using 226Ra "hot" sources, in the 1960s and early 1970s, through manual afterloading for treating gynaecological cancers with the same sources in the 1970s and 1980s, to high-dose rate (HDR) remote afterloading on a microSelectron HDR machine, from 1989 on. This progression in brachytherapy is discussed, and specific applications to various tumour sites are presented, including long-term results of a personal series of 106 patients with cancer of the uterine...
Schreeg ME, Radkin M, Haugland J, Murphy BG, Rushton S, Linder KE.Ameloblastic carcinoma is a malignant odontogenic neoplasm that has been reported only rarely in veterinary species. A 16-y-old Arabian crossbred mare was presented for evaluation of a hard mass on the body of the mandible, with evidence of osteolysis on radiographs. Incisional biopsies revealed an invasive neoplasm comprised of spindloid epithelial cells with a high mitotic count and partial dual cytokeratin-vimentin immunoreactivity. The horse was euthanized because of rapid tumor progression 3 mo after presentation. Postmortem evaluation revealed partial obliteration of the mandible by a ...
Brinsko SP.Genital neoplasms in the male horse are relatively uncommon. Squamous cell carcinomas and squamous papillomas are the most commonly diagnosed neoplasms of the penis and prepuce. Geldings appear to be overrepresented for these types of neoplasms, and accumulation of smegma may be a contributing factor. Early diagnosis and treatment are essential for salvaging these organs before lesions become excessively large and invasive or are allowed to metastasize. Newer treatment modalities such as 5-fluorouracil appear to be promising alternatives to surgical excision. Although generally considered to b...
Schaffer PA, Wobeser B, Martin LE, Dennis MM, Duncan CG.To identify epidemiological trends in cutaneous neoplasms affecting equids in central North America and compare them with previously reported trends. Methods: Retrospective case series. Methods: 3,351 cutaneous biopsy specimens from 3,272 equids with a neoplastic diagnosis. Methods: Diagnostic reports from 2 diagnostic laboratories (Colorado State University and Prairie Diagnostic Services Inc) were reviewed for frequency of specific lesions and epidemiological trends. Variables included in analyses (if known) were age, sex, breed, geographic location, date of diagnosis, location of neoplasm o...
Smrkovski OA, Koo Y, Kazemi R, Lembcke LM, Fathy A, Liu Q, Phillips JC.Performance and clinical characteristics of a novel hyperthermia antenna operating at 434 MHz were evaluated for the adjuvant treatment of locally advanced superficial tumours in cats, dogs and horses. Electromagnetic simulations were performed to determine electric field characteristics and compared to simulations for a flat microwave antenna with similar dimensions. Simulation results show a reduced skin surface and backfield irradiation and improved directional irradiation (at broadside) compared to a flat antenna. Radiated power and penetration is notably increased with a penetration depth...
Takeuchi K, Hagiwara Y, Kanaya K, Wada K, Shiba M, Kato Y.The diagnosis of pituitary carcinoma cannot be made easily histologically, and most cases of pituitary carcinoma are diagnosed only after the clinical detection of metastasis. Distant metastasis of pituitary tumor occurs in 0.1% to 0.2% of cases and has been reported in the liver, bone and central nervous system, with only one case of metastasis to the cauda equine reported. This study describes a rare case of the drop metastasis of adrenocorticotropic hormone-producing pituitary adenocarcinoma to the cauda equina, causing cauda equina syndrome.
Millward LM, Hamberg A, Mathews J, Machado-Parrula C, Premanandan C, Hurcombe SD, Radin MJ, Wellman ML.A 6-year-old female Rocky Mountain horse was presented for evaluation of draining tracts and distal limb subcutaneous edema on the left front and left hind limbs that had been present for 2 weeks. Direct smears of fluid collected by fine-needle aspiration of subcutaneous fluid from both limbs were highly cellular with a predominance of eosinophils accompanied by numerous, moderately atypical, variably granulated mast cells. The cytologic diagnosis was mast cell tumor (MCT) with prominent eosinophilic infiltration with a differential diagnosis of eosinophilic granuloma. Histologic evaluation of...
Hubert JD, Burba DJ, Moore RM.To describe a laparoscopic technique for granulosa cell tumor removal using a vessel sealing device (LigaSuretrade mark) in standing mares. Methods: Retrospective study. Methods: Eight mares (8-24 years old; weighing, 406-525 kg). Methods: Before surgery, ovarian size and adjacent body wall thickness was determined by ultrasonography. Mares were sedated and after local anesthesia (inverted L and local infiltration), laparoscopic cannulation was performed without insufflation. The mesovarium was anesthetized and the LigaSure instrument applied to the mesovarium for hemostasis and resection to r...
Cole R, Chesen AB, Pool R, Watkins J.Equine mast cell tumors are typically benign solitary growths of the head, neck, trunk, or limbs. When involving the limbs, these masses tend to be adjacent to joints without involving them. In radiographs there is often a well-circumscribed soft tissue mass with granular mineralization. The Arabian breed appears to be over represented. Surgical removal is usually curative. In this report, we describe the diagnosis, clinical features, and management of mast cell tumors in the rear limb of a horse.
Pinzón-Osorio CA, Meneses-Martínez H, Botero-Espinosa L, Herrera-Luna CV.A 10 year-old endurance Arabian mare was presented with an invasive, firm, multilobulated mass at the left ventral face of the tongue. The mare had a history of four months of ptyalism, dysphagia, severe halitosis, and dysmastication. The Evaluation of the horse included physical and oral examination, complete blood count and serum biochemistry profile, computed tomography evaluation of the head, and histopathology of the mass. The computerized tomography (CT) head scan showed the homogeneous mass in the oral cavity confirming the degree of invasion on the tongue, as well as a small mineral fo...
Aida Y, Okada K, Kageyama R, Amanuma H.Tumor-associated antigens that are expressed in lymphosarcoma B cells of cattle with enzootic bovine leukosis had been analyzed in terms of their reactivity with 13 monoclonal antibodies (MAB). By use of flow cytometry and radioimmunoprecipitation, 1 of the MAB (c143) that recognized a tumor-associated antigen cross-reacted with blood lymphocytes (BL) from various mammalian species. By use of flow cytometry, the c143 MAB reacted with 10 to 49% of BL derived from human beings, mice, dogs, horses, pigs, llamas, sheep, goats, and cattle. Titer of the c143 MAB with BL from horses, pigs, human bein...
Claes AN, Ball BA.Anti-Müllerian hormone (AMH) plays a major role in sexual differentiation, Leydig cell differentiation, and folliculogenesis. In addition, AMH has clinical value in equine practice. In stallions, AMH can serve as an endocrine marker for equine cryptorchidism and as an immunohistochemical marker for Sertoli cell tumors. Considering that AMH is also an ovarian specific product, intact mares can be differentiated from ovariectomized mares. Peripheral AMH concentrations reflect the follicular population in mares, and therefore, are useful in the assessment of ovarian reserve and reproductive life...
Cochrane CA, Freeman KL, Knottenbelt DC.Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor-like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue-derived cells with normal dermal fibroblasts grown from primary cell cultures. All three ce...
Curnow B, Rich AF, Ireland J, Correa DC, Dunn J, Jenkins D, Carslake H, Ressel L.Although the equine sarcoid is the most common skin neoplasm in domesticated horses, histopathological characteristics have not previously been evaluated for association with recurrence. The aim of this retrospective cohort study was to investigate clinical and histopathological features of excised equine sarcoids and to evaluate their association with recurrence at the original surgical site and at new sites. Clinical records and excisional biopsies from 106 equine sarcoids from 64 horses referred to Leahurst Equine Hospital, University of Liverpool, between March 2010 and February 2015 were ...
Hewes CA, Sullins KE.To determine outcome for equids with cutaneous neoplasms treated with cisplatin-containing biodegradable beads, alone or in conjunction with debulking. Methods: Retrospective case series. Methods: 56 horses, 1 zebra, 1 donkey, and 1 mule. Methods: Medical records were reviewed. Follow-up information was obtained through telephone conversations with owners and trainers of the animals. Results: 22 tumors were sarcoids, 6 were fibrosarcomas, 1 was a fibroma, 2 were peripheral nerve sheath tumors, 11 were squamous cell carcinomas, 14 were melanomas (13 gray horses and 1 bay horse), 1 was a lymphos...
Davis CR, Barr BC, Pascoe JR, Olander HJ, Dubey JP.Hepatic sarcocystosis was diagnosed in a horse in association with refractory bacterial osteomyelitis and plasma cell tumor of the maxilla and hepatic salmonellosis. Gross lesions included pleural, pericardial, and peritoneal effusions, hepatomegaly, gastric ulceration, colonic edema, and proliferative tissues filling 2 maxillary dental alveoli. Histologically, liver was characterized by severe suppurative, necrotizing, periportal hepatitis, and severe periacinar necrosis. Hepatocytes frequently contained protozoal schizonts in various stages of development. In mature schizonts, merozoites wer...
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...
Horbal A, Dixon PM.A 4-year-old thoroughbred cross mare was referred to the University of Edinburgh Veterinary School Equine Hospital for treatment of a soft tissue tumor on the buccal gingival margin of the rostral right maxillary cheek teeth. The lesion was initially surgically excised and diagnosed as a fibrosarcoma via histopathology. Adjunctive treatment with intralesional cisplatin chemotherapy was begun. The tumor recurred and was repeatedly treated with intralesional cisplatin injections and additional surgical resection over the course of 14 weeks. Despite the initial poor response to treatment, no furt...
Foley GL, Valentine BA, Kincaid AL.In a retrospective study, cutaneous melanocytic tumors from 18 horses, less than 2 years old, were examined histopathologically and clinical follow-up requested. Melanocytomas (benign melanomas) occurred in a variety of breeds and in horses of varied coat color. The age of the horses at the time of biopsy ranged from 3 weeks old to 2 years old. Four melanocytomas were congenital, 11 melanocytomas were acquired by 1 year of age, and three were acquired prior to 2 years of age. Of the 18 horses, five were male, and 13 were female. All tumors were solitary and located on the legs or trunk; none w...
