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.
Garma-Aviña A, Valli VE, Lumsden JH.Four cases of equine congenital cutaneous papillomatosis were found during a review of 555 cutaneous tumours received at the pathology department, Ontario Veterinary College, during a 10-year period. A fifth case received after that period was also included. Two of the tumours were found in Thoroughbreds, one in a Standardbred, one in an Arabian and in one case the breed was not specified. The anatomical locations were the rib cage, head, hind leg and 2 on the forehead.
Riggott JM, Quarmby WB.A surgically excised tumour from the thoracic wall of a hunter mare was diagnosed as a fibrosarcoma on histological examination. Its recurrence necessitated further surgery 6 weeks later. Because of the invasive nature of the lesion a prolonged course of chemotherapy was administered postoperatively. The tumour did not recur a second time.
Amtmann E, Müller H, Sauer G.Bovine papilloma virus (BPV) appears to be the etiological agent of common equine connective tissue tumors. We investigated the physical state of the viral DNA within such tumors and found no indication for integration into the host genome. The BPV genomes were present as free circular episomes. Two equine sarcoids were shown to contain multiple copies of free circular BPV type 1 (BPV-1) DNA. When the tumors were digested with several single-cut restriction enzymes, there were only form III BPV-1 DNA sequences could be revealed. One of the sarcoids contained, apart from wild-type BPV-1 DNA, a ...
Nickels FA, Brown CM, Breeze RG.A unilateral pulmonary granular cell tumor occurred in a Thoroughbred mare with longstanding respiratory disease wrongly attributed to chronic obstructive pulmonary disease. The clinical features, radiology and endoscopic appearance permitted an accurate diagnosis, which was supported by subsequent necropsy and histologic examination. Obstructive pulmonary disease was ruled out after measurement of arterial blood gases and maximum intrathoracic pressure changes, and after microscopic examination of the lung.
Grier RL, Brewer WG, Paul SR, Theilen GH.Forty-five ocular squamous cell carcinomas (SCC) in 17 cattle and 8 horses were treated by radiofrequency hyperthermia, resulting in 80% complete regression and 16% partial regression. Tumors were histologically diagnosed as SCC; 50% of the tumors were recurrent, having been treated previously by surgery, cryosurgery, radiation, or immunotherapy. After hyperthermic treatment, most animals were available for tumor measurement at 4 to 6 weeks and at 8 to 16 weeks, with a final observation period of 2 to 10 months for all. Complete regression occurred in 8 of 12 tumors given a second hyperthermic...
Sheahan BJ, Atkins GJ, Russell RJ, O'Connor JP.Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis. Consistent haematological changes were absent. One mare had lymph node involvement but no neoplastic lesions in the viscera. Microbiological examination of tumour tissue showed coryneform bacteria; there was no evidence of C-type or lytic viruses or of reverse transcriptase. Prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.
Stick JA.In three horses with abdominally retained testicles, teratomas with cyst formation were found. Bone development in the head of the epididymis, near the vascular supply of the tumor, was a consistent finding. Aspiration of the cystic portion of the tumor was necessary for surgical removal in two cases. Although germinal carcinoma cells have been suggested as the cause of teratomas, evidence of malignancy was not seen in any of the three tumors.
Ek N.Studies of Pr protein concentrations in sera of sick horses were carried out using ’s (1965) immunodiffusion technique. Relative values against a chosen standard of 100 were determined for a total of 102 horses. Horses with acute infections had Pr protein values significantly above the normal. The highest individual Pr protein value recorded in this group was 202. Horses suffering from acute laminitis and malignant tumours also had increased Pr protein values. There was a positive correlation between the Pr protein value and the blood leucocyte count and a negative correlation between the P...
Broström H, Bredberg-Rådén U, England J, Obel N, Perlmann P.Cell-mediated immunity in horses with sarcoid tumor against sarcoid antigens was studied in vitro by means of mixed lymphocyte tumor cell culture assay and lymphocyte-mediated cytotoxicity of 52Cr-labeled target cells. When Mc-1 sarcoid cells were used as stimulatory cells for peripheral blood lymphocytes in the mixed lymphocyte tumor cell assay, a clear difference in the kinetics of the generated lymphocytic proliferative response could be detected between sarcoid and control horses. With sarcoid horses, their proliferative maximum was reached 3 days earlier than that of the control horses, a...
Summers PM, Wells KE, Adkins KF.The features of an ossifying ameloblastoma in a 5-year-old gelding are described. The tumour developed in the angle of the right mandible and microscopically consisted of multiple follicles and islands of epithelial tissue adjacent to which were trabeculae of bone, osteoid and compact collagenous tissue.
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...
Parker GA, Novilla NM, Brown AC, Flor WJ, Stedham MA.A granular cell tumour (myoblastoma) occurred in the lung of an aged mare. Multiple greyish-white neoplastic nodules of various sizes almost replaced one lung. Histologically, the neoplasm consisted of small clumps of granular cells in a stroma composed of thick bands of collagen and numerous capillaries. The globoid or stellate neoplastic cells were characterized by a large number of eosinophilic, PAS-positive, diastase-resistant cytoplasmic granules. Ultrastructurally, the granules were of two types: (a) homogeneous, electron-dense granules and (b) multimorphous granules that resembled cell ...
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.
Kofler J, Kübber-Heiss A, Schilcher F.Clinical, ultrasonographic and pathological findings of a cutaneous, multilocular T-cell lymphosarcoma (malignant lymphoma) in a 13-year-old, brown Austrian warmblood mare are reported. The horse was under clinical observation, and the tumours were sonographically monitored over an 8 month period, revealing worsening of body condition, weight loss, lameness of the left hindlimb and a slight increase in the tumours size. Most of the tumours were covered by normal skin, one showed ulceration. Ultrasonography of the tumours allowed accurate anatomical localization in relation to the adjoining tis...
Fadok VA.Papules and nodules are common lesions on horses and have a variety of underlying causes. This article addresses inflammatory and congenital nodules primarily, including urticaria, erythema multiforme, those nodules caused by infectious agents, epidermoid and dermoid cysts, and the uniquely equine skin tumor, the sarcoid. The eosinophilic nodules and other tumors are covered elsewhere in this issue. Diagnostic and therapeutic approaches to each of the diseases are emphasized.
Potter K, Anez D.A 17-year-old Quarter Horse mare was examined to determine the cause of a vulvar mass. Differential diagnoses for the swollen, ulcerated tissue included hypersensitivity reaction to insect stings or bites and cutaneous neoplasia. During the next 4 months, the mass enlarged involving the skin of the perineum and ventral aspect of the abdomen with secondary dependent edema of both hind limbs. Histologic examination of biopsy and necropsy specimens revealed changes consistent with a diagnosis of mycosis fungoides (cutaneous T-cell lymphoma). Diagnostic features included invasion of neoplastic lym...
Reid N.A round mass 4 cm in diameter was present on the proximal rostro-lateral border of the right pinna of a 10-year-old, gelded, Paint horse. A preliminary histopathological diagnosis of a potential squamous cell carcinoma and peripheral nerve sheath tumor was made, and the lesion was resected at the base of the lateral edge of the ear. Une masse ronde de 4 cm de diamètre était présente sur le bord rostrolatéral proximal du pavillon de l’oreille droite d’un Paint horse castré âgé de 10 ans. Un diagnostic histopathologique préliminaire d’un carcinome squameux et d’une tumeur de la ...
Meinecke B.The present study comprises 31 mares, that showed a permanent unilateral enlargement of the ovary. In 29 patients the ovary in question was removed by a flanc laparotomy in the standing animal. In the histopathologic examination a granulosa cell tumor was diagnosed in 23 cases, a fibroma twice and a teratoma, hematoma, leiomyoma and a cystic ovary each once. Due to the endocrine activity of the granulosa cell tumor, the clinical picture was characterized by changed behaviour and atrophy of the contralateral ovary. Clinically the ovarial blastomas (teratoma, leiomyoma, fibroma) could not be dif...
Smith BL, Morton LD, Watkins JP, Taylor TS, Storts RW.A 16-year-old cryptorchid Quarter House with colic had a large, lobulated soft-tissue mass to the left of the pelvic inlet. At surgery, 2 large multilobulated pedunculated masses were removed. A large blood vessel enveloped by one of the masses was damaged, and the horse exsanguinated. Postmortem examination of the abdomen revealed the masses to be malignant seminoma, with multiple sites of metastasis.
Oikawa M, Ohishi H, Katayama Y, Kushiro A, Yoshikawa H, Yoshikawa T.A mass developed in the mandibular gingiva of a thoroughbred racehorse. When the horse could no longer eat unassisted, it was killed and immediately autopsied. Macroscopically, the mandible exhibited extensive osteolysis, with only a small amount of bone remaining around the tooth roots. The cut surface of the mass around the mandible consisted of neoplastic medullary tissue, in which osteogenesis was observed. The medullary tissue was composed of pleomorphic medium-sized to large cells, interlaced by collagen bundles. These cells had large, pale, round or ovoid, sometimes cleaved nuclei, with...
Held JP, Patton CS, Toal RL, Geiser DR.A thyroid carcinoma was diagnosed in a 14-year-old competitive trail horse with a 3-month history of work intolerance. Abnormal findings included low base-line triiodothyronine (T3) and thyroxine (T4) values, a large thyroid gland and decreased work tolerance. Nuclear medicine scanning revealed displacement of the right thyroid gland by a mass. Needle biopsy of the mass revealed neoplastic changes compatible with thyroid carcinoma. After removing the tumor surgically, T3 and T4 values returned to normal. Subsequently, the horse was able to compete successfully. Horses with work intolerance com...
Facemire PR, Chilcoat CD, Sojka JE, Adams SB, Irizarry AR, Weirich WE, Morisset SS, Dutweiler VA.A 7-year-old warmblood mare was referred because of a respiratory tract disorder; pulmonary granular cell tumor was diagnosed. Pulmonary granular cell tumor is a locally invasive but rare type of tumor with low metastatic potential. The entire right lung was resected to ensure removal of all neoplastic tissue. The horse recovered well and has minimal difficulties functioning with one lung. Most of these tumors are diagnosed during postmortem examination. To our knowledge, this is the first report of pulmonary granular cell tumor treated by complete lung resection in a horse.
Beatriz FR, Marta VG, María MC, Joaquín JF, Esther DF, Luis-Javier EC, Gabriel MD, Manuel IG.An 8-year-old mare mule was presented with a facial mass and history of anorexia, unilateral epistaxis and purulent nasal discharge. The facial mass was encountered from the ventral to the lateral right canthus of the eye up to the facial crest. Thoracic ultrasonography showed five rounded masses. A standing CT under sedation was performed revealing a huge extension and infiltration on surrounding tissues. Due to the extension, type of lesions, outcome and suspicion of metastasis, the owner chose to euthanize the patient. Necropsy confirmed the presence of tumoral lesions spread into the lungs...
Rapisarda G, Marino F, Ferrara G, Gioffrè F, Galofaro V.Here we present a case of preputial benign fibrous histiocytoma in a 7-year-old mule. This case was treated surgically. Pathologic analysis and diagnosis of these lesions were based on a combination of light microscopy and immunohistochemistry. Histologically, the tumour was composed primarily of a storiform pattern of fibroblastic and poligonal cells. In immunohistochemistry, except for consistent immunoreactivity for vimentin, nearly all tumour cells were positive for CD68, S-100 protein, pan-cytokeratin, alpha-smooth muscle actin, and desmin. Benign fibrous histiocytoma of the prepuce in mu...
Mayr B, Resch S, Hepperle S, Brem G, Reifinger M, Schaffner G.Tumour suppressor p53 is critical in a broad panel of tumour types in human, mouse and other mammals. Regions of the promoter and exon 1 play an important role in expression of p53. In the present study, the DNA sequences of promoter and exon 1 regions of four domestic animal species (dog, cat, horse and cattle) are determined and compared with experimental rodents (mouse, rat and hamster) and man. A broad panel of tumour types have been investigated for mutations in this regulatory area in 90 canine, 136 feline, 25 equine and 10 bovine patients. No mutation was detected in any of the tumours ...
Hildebrandt L, Jäger K, Snyder A, Sobiraj A.The case report describes a narrowing of the spinal canal in the lumbar and sacroiliac regions with entailing acute recumbency in a nearterm 17-year-old Welsh B Pony mare. The reason for recumbency was metastases of a malignant melanoma in the spinal canal of the lumbo-sacral region, where the tumour had invaded the dura mater and applied severe pression on the spinal cord over a length of 10 cm. Clinical findings, laboratory diagnostics, pathological-anatomical and histopathological findings are presented.
Daicker B, Gywat L, Keller M, Spiess B, Brückner R.The authors describe peculiar tumors with brown-white piebald anterior surface, which had grown bilaterally from the corpora nigra (C.N.) of an adult horse and occluded the pupils. The surgical procedure for removing the larger tumor and the postoperative treatment are described. The findings by light and electron microscopy suggest that the tumor represent a so-called adenoma of the iris pigment epithelium. The white patches on its surface consist of newly formed Descemet-like material produced by displaced corneal endothelial cells, which have probably grown on the tumor after contact with t...
Kelley LC, Hill JE, Hafner S, Wortham KJ.Spontaneous equine pulmonary granular cell tumors were diagnosed in six mature horses at slaughter. These tumors were grossly recognized as multiple (5/6) or single (1/6) creamy white, firm nodules. The tumors, located adjacent to bronchi and bronchioles, often invaded airways, resulting in partial to complete occlusion of the lumina. Neoplastic cells were rounded to polyhedral with numerous eosinophilic cytoplasmic granules that reacted uniformly positive with S-100 and neuron-specific enolase antibodies and multifocally with glial fibrillary acidic protein antibodies. These cells were negati...
Matsuda K, Kousaka Y, Nagamine N, Tsunoda N, Taniyama H.A 20-year-old thoroughbred mare had a mass in the right kidney. The mass was encapsulated with fibrous capsule and composed of variably-sized papillary projections lined by a single layer of flattened to cuboidal neoplastic epithelial cells with no cytological and nuclear atypia. Immunohistochemically, the neoplastic cells were broadly positive for cytokeratin AE1/AE3 and granular staining for alpha-1-antitrypsin was focally detected; this immunohistochemical property was similar to that of the normal distal nephron. From these results, this case was diagnosed as papillary renal adenoma of dis...
Adams R, Calderwood-Mays MB, Peyton LC.A highly successful surgical technique for removing cutaneous tumors in humans was used in seven horses with cutaneous squamous cell carcinoma (n = 3) or sarcoid (n = 4). In humans, the complete underside of the tumor is evaluated histologically by processing horizontal sections from the tumor base, and orientation between the wound surface and the undersurface of the excised tumor is maintained by mapping both surfaces. The technique ensures that small foci of residual tumor can be located accurately and removed. Based on our experience, three modifications of the human technique are suggeste...
Rabelo AA, Maranhão RPA, de Miranda ALS, Ocarino NM, Amaral CI, Paes PRO, Monteiro NCC, Fantini P.A 25-year-old mixed-breed equine with separate nodular cutaneous lesions in the right thoracic limb (RTL) and right ventral abdominal region was admitted to a Veterinary Hospital in Belo Horizonte, Minas Gerais. Fine-needle aspiration cytology was performed on the RTL lesion and superficial cervical lymph node, and the results were suggestive of a malignant neoplasm known as myxosarcoma. Due to the unfavorable prognosis, the animal was euthanized. Based on the macroscopic and microscopic findings, the diagnosis of metastatic cutaneous myxosarcoma was confirmed. Although rare, this tumor should...
Rapezzano G, Foote A, Petrini F, Pereira R, Marcatili M.A newborn Thoroughbred filly presented with a large mass located on the ventro-rostral aspect of the mandible. The mass was surgically removed under general anaesthesia. Upon gross examination, the mass was well circumscribed with a heterogeneous lobulated appearance. The results of histopathology and immunohistochemistry were consistent with a diagnosis of congenital fetal rhabdomyoma. On follow-up at six months post-surgical excision, no abnormalities were noted on clinical examination.
Mudge MC, Green E.Radiotherapy is a valuable treatment option for equine tumors that have a high rate of recurrence or where complete surgical resection may damage vital structures. Teletherapy, brachytherapy, and plesiotherapy have been used successfully for the treatment of a variety of tumors and locations in the horse. Radiobiology, treatment protocols, side effects, and patient management are reviewed, with a focus on linear accelerator-based teletherapy. There is evidence of good success rates for treatment of periocular sarcoids and squamous cell carcinoma but teletherapy treatment is often limited to tu...
Greet TR, Bathe AP.This paper describes the use of a linear stapling device as an aid to unilateral ovariectomy in nine mares with granulosa thecal cell tumours. The intraoperative and postoperative complications are described and follow up details on each case are presented.
Prutton J, Tucker R.Neoplasia has been reported to involve the majority of the urinary system of the horse, with tumors affecting the kidneys and bladder most comprehensively described. Primary tumors of the external genitalia are relatively common in the horse and are easily identified on clinical examination while primary tumors of the upper urogenital tract are uncommon. This article will highlight the common tumors, their clinical presentations, and discuss potential medical and surgical treatment options available. The less common neoplasms will be mentioned but not discussed in depth.
Fintl C, Wilkins PA.There are a number of unusual tumors in the horse. Gross tumor characteristics, anatomical location, and signalment may assist with identification. Clinical pathology is often unrewarding with non-specific findings, while fine needle aspirates may not obtain sufficient tissue material to confirm a diagnosis. Although regular staining of biopsy material may be sufficient, immunohistochemistry markers may be required, especially in less differentiated tumors. The prognosis is dependent on the type, location, tumor size as well as on metastatic spread. A selection of unusual and rare tumors that ...
Nieman RT, Lamim LI, Del Fava C.Fetal loss in mares can result from a range of causes, including infectious agents or noninfectious conditions such as neoplasia, which may originate from either the fetus or the dam. Among neoplastic conditions, teratomas are rarely reported and, to date, have not been described in the equine fetal testis. Teratomas arise from the partial differentiation of pluripotent germ cells and may occur in young and adult horses, typically in cryptorchid testes. Their gross and histopathological features vary widely between cases. This report describes a rare case of bilateral fetal testicular teratoma...
Kegler K, Mundle K, Walliser U, Wohlsein P.Schwannomas arising in the parotid gland are rare in man and are not documented in domestic animals. This report describes the clinical, morphological and immunohistochemical findings of a benign schwannoma in the parotid gland of a 12-year-old warmblood gelding. A slow-growing mass was surgically excised from the parotid gland and did not recur within the following 6 months. The tumour was well circumscribed and was composed of densely packed spindle cells partly arranged in an Antoni A pattern and intermixed with hypocellular areas resembling the Antoni B pattern. Tumour cells expressed vime...
Jaeschke G, Rudolph R.In a review supplementary to prior evaluations further hematological or cytodiagnostic aspects respectively of equine leucosis are discussed. Leukemic nature of the disease is characterized by increased count of normal blood cells or by the presence of morphologically non-differentiated cells in circulating blood or by disorder or loss of function of blood cells respectively. Thrombocytopenia in the most cases is accompanied by anemia, leukemia and tumor cell infiltration in bone marrow. Tumor cells in circulating blood indicate their presence in bone marrow too. In cases of equine leucosis wi...
Hoque S, Senba H, Tsunoda N, Derar RI, Watanabe G, Taya K, Osawa T, Miyake Y.To clarify the endocrinological characteristics of the mares with granulosa theca cell tumor (GTCT), peripheral plasma samples from the 6 mares affected with GTCT were collected before and after the surgical removal of the affected ovary. Concentrations of testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive-inhibin (ir-INH), progesterone (P) and estradiol-17beta (E(2)) in the plasma samples were measured by radioimmunoassay. Before removal of GTCT in all cases, the concentrations of T were significantly higher than those of normal mares at the breedin...
Zelli R, Sylla L, Monaci M, Stradaioli G, Sibley LE, Roser JF, Munro C, Liu IK.Granulosa-theca cell tumors (GTCTs) are able to secrete variable amounts of sex steroids and immunoreactive inhibin (ir-INH). Although the pituitary appears to be affected by the presence of a GTCT, pituitary responsiveness to exogenous GnRH has not been examined. The aims of the present study were to: (i) assess the plasma hormone concentrations of ir-INH, gonadotropins and sex steroids in eight mares with GTCT and (ii) assess the responsiveness of pituitary gonadotroph cells to exogenous GnRH stimulus both before and after tumor removal. In seven mares, the contralateral ovary was firm, smal...
Ohmuro K, Okada K, Satoh A, Murakami K, Satake S, Asahina M, Numakunai S, Ohshima K.A thoroughbred horse, gelding, gray color, aged 19 years old had cutaneous melanomas from the root to the middle of the tail, and throughout the connective tissues of the whole body. Histologically, the tumors were diagnosed as mature melanotic melanomas characteristically deposited with abundant melanin pigment. Examined with an electron microscope, melanosomes were electron opaque without internal structure (stage IV), or as mature granular and lamellar types. Most of them were fused with each other, and formed compound melanosomes, which was similar to internal melanin aggregates in shape. ...
