Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Neoplasm
Neoplasms in horses refer to abnormal tissue growths that can be benign or malignant, affecting various body systems. These growths arise from uncontrolled cellular proliferation and can occur in different forms, including tumors and cancerous lesions. Equine neoplasms can impact the skin, gastrointestinal tract, reproductive organs, and other areas, with common types including melanomas, sarcoids, and squamous cell carcinomas. Diagnosis often involves clinical examination, imaging, and histopathological analysis. Treatment and prognosis vary depending on the type, location, and stage of the neoplasm. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, diagnosis, treatment options, and outcomes associated with neoplasms in equine patients.
[Cutaneous vascular hamartoma in a foal]. Vascular hamartomas are rare malformations in foals that typically present as painless masses of the skin or subcutaneous tissue. This case report describes a newborn foal with a vascular mass over the right shoulder. Complete surgical excision was performed at seven days of age. Histologically, the lesion was found to be a well-defined dermal vascular proliferation consistent with a vascular hamartoma. The healing process was uneventful, and no recurrence occurred six months postoperatively. This case adds a rare location on the scapula to the literature and confirms surgical removal as an ef...
Equine Sarcoid: From BPV-Driven Oncogenesis to Host-Sustained Tumor Persistence. Equine sarcoid is the most common cutaneous neoplasm of equids and represents a distinctive model of virus-associated tumor persistence. Although bovine papillomaviruses, particularly BPV-1 and BPV-2, are recognized as the main etiological agents, viral infection alone does not fully explain the clinical heterogeneity, frequent recurrence, and limited spontaneous regression of these lesions. This review summarizes current evidence on the molecular and cellular mechanisms underlying equine sarcoid pathogenesis, with emphasis on the interaction between BPV infection, host signaling pathways, tum...
Intratracheal Leiomyosarcoma in a 13-Year-Old German Riding Pony Mare. A 13-year-old German Riding Pony mare was referred for evaluation of progressive respiratory noise and mixed dyspnoea, which rapidly deteriorated to respiratory distress. Clinical examination revealed marked rattling inspiratory and expiratory tracheal sounds and severe, rattling, vesicular lung sounds. Arterial blood gas analysis demonstrated moderate hypoxaemia (partial pressure of arterial oxygen 76 mmHg at rest). Upper airway endoscopy identified a pink, cauliflower-like pedunculated mass originating from the dorsal tracheal wall approximately 15 cm cranial to the tracheal bifurcation, cau...
Concurrent Small Intestinal Neoplasia And Large Colon Volvulus In A Standardbred Yearling. Large colon volvulus is a common, life-threatening cause of colic in horses. Gastrointestinal neoplasia is a rare cause of abdominal pain in young horses. A 1-year-old Standardbred colt presented with acute colic unresponsive to medical treatment. An exploratory laparotomy identified extensive gastrointestinal pathology, and euthanasia was elected due to a poor prognosis. Necropsy revealed a 360-degree volvulus of the caecum and large colon with adhesions, enterotyphlocolitis, and a well-circumscribed mesenteric mass arising from the small intestine. Histopathology in combination with immunohi...
Leptomeningeal dissemination of a poorly differentiated carcinoma involving the trigeminal ganglion in a horse: a case report. Neoplastic conditions involving cranial nerves are uncommon in horses and represent a significant diagnostic challenge. Leptomeningeal dissemination is a recognized mechanism of tumor progression in aggressive neoplasms but is rarely reported in this species. A 15-year-old mixed-breed horse with a history of periocular squamous cell carcinoma treated by enucleation three years earlier developed progressive neurological signs. Initial differential diagnoses included metastatic neoplasia and equine protozoal myeloencephalitis. Due to rapid neurological deterioration, euthanasia and necropsy were...
Testicular Disorders in Equids: A Case Series. Equine testicular disorders represent a diverse group of conditions that impact the longevity of a stallion's breeding career. Stud farm veterinarians should be familiar with the variety of clinical presentations and diagnostic options for these conditions. This retrospective case series reports 57 cases of testicular abnormalities in stallions and donkeys presented to the clinic for further diagnostics and treatment. These disorders included neoplasia (three unilateral and one bilateral seminoma; two Sertoli cell tumors; two Leydig cell tumors; and one malignant mixed sex cord-stromal tumor),...
Risk Factors for Disease in Military Working Equines. Diseases can impact Military Working Equids (MWEs) readiness and limit days in service. The objectives of this study are to categorize diseases in MWEs and evaluate potential risk factors for disease. Methods: Pathology reports from MWEs from 2005 to 2025 were retrieved from the Joint Pathology Center archives. Disease processes with ≥5 cases were evaluated for potential risk factors, including MWE breed, sex, neuter status, geographic location, and age at sampling. Results: Diagnoses included inflammation (n = 30), neoplasia/proliferation (n = 24), within normal limits (n = 12),...
Oxidative Stress and Immunomarkers in Equine Dermal Melanomatosis: Single-Case Comparison with Healthy Individual. Dermal melanomatosis is a common tumor in grey horses, characterized by cutaneous/subcutaneous lesions with metastatic potential. While clinically well-described, oxidative stress involvement remains poorly understood. This case report compared oxidative stress markers and antioxidant enzymes' activities in total protein extracts from melanomatosis lesions (grey horse) versus healthy control skin (black horse), alongside histopathology and immunohistochemistry, to correlate oxidative imbalance and tumor behavior. Melanomatosis tissue exhibited decreased antioxidant defenses confirmed by catala...
Intratumoral para-toluenesulfonamide as a tumor-ablative therapy for equine cutaneous tumors: a case series of three horses. Equine neoplasia, including sarcoids, melanomas, and squamous cell carcinomas, presents therapeutic challenges due to recurrence and limitations of conventional treatments. Para-toluenesulfonamide (p-TLS) is a tumor-ablating agent that is associated with localized tumor necrosis and subsequent lesion resolution. It has been evaluated in human clinical settings as an intratumoral treatment of malignant airway obstruction caused by non-small cell lung cancer. This study aimed to describe the clinical outcomes and tolerability of intratumoral p-TLS in equine neoplasia. Three equine cases, includi...
Clinical and pathologic findings of splenic tumours in four horses: a case series. Splenic tumours are rare in horses, with limited published literature consisting primarily of individual case reports and one hepato-splenic lymphoma case series. This case series analyses the clinical presentation, diagnostic findings and clinical outcomes of four cases of splenic neoplasia that presented to a university referral hospital over a three year period (2022-2025). Methods: Presented are two cases of primary splenic lymphoma, and two cases of metastatic melanoma. Three cases (75%) presented with chronic, non-specific clinical signs including weight loss, colic and ventral oedema. O...
Electrochemotherapy Following Surgical Cytoreduction for the Treatment of Recurrent Equine Sarcoids: A Retrospective Study of 23 Lesions. Despite the wide range of therapeutic options currently available for equine sarcoids, recurrence of these lesions remains a major clinical challenge. Consequently, the identification of effective strategies for the management of recurrent sarcoids remains an important objective in equine oncology. The aim of this retrospective study was to evaluate the clinical outcome of surgical cytoreduction combined with intraoperative electrochemotherapy in horses affected by recurrent equine sarcoids. Medical records of horses treated between July 2018 and August 2025 at the Veterinary Teaching Hospital...
Testicular seminoma: clinical, imaging, and histologic features in nine horses. Testicular seminomas in horses are infrequently reported in the veterinary literature and long-term survival and metastatic potential are not well documented. Objective: Describe the clinical, imaging, and histologic features in 9 horses with testicular seminoma. Methods: Medical records of 9 horses diagnosed with testicular seminoma at a referral hospital between 2000 and 2024 were reviewed. Methods: Horses were included if seminoma was confirmed on histopathology from biopsy or necropsy. Information retrieved included signalment, history, clinical pathology, ultrasonographic findings, treatm...
Mammary neuroendocrine tumor in a mare. A 10-y-old American Paint Horse mare was presented to the Equine Field Services at Virginia-Maryland College of Veterinary Medicine (Blacksburg, VA, USA) for evaluation of mastitis and a possible abscess in the right mamma. Histologic evaluation of a mammary biopsy revealed a densely cellular, infiltrative neoplasm with cells arranged in packets supported by thin stroma. In a neuroendocrine immunohistochemistry panel, the neoplastic cells did not immunolabel for neuron-specific enolase or synaptophysin, positively immunolabeled for chromogranin A, and had moderate scattered immunolabeling for ...
Integrated transcriptomic profiling reveals oncogenic pathways and chimeric transcripts in equine sarcoid lesions with predominant BPV1 detection. Sarcoids are the most common cutaneous tumors in horses, representing up to 90% (35%-90%) of skin neoplasms. Mostly caused by Bovine Papillomavirus (BPVs) infections, sarcoids are highly resistant to therapy and prone to recurring, posing a significant threat to equine health. The aim of this study is to explore molecular pathogenetic mechanisms underlying the development of equine sarcoids, by applying transcriptomic approach. After testing samples for viral DNA, both mRNA and small RNA expression was analyzed via high-throughput Illumina sequencing comparing 12 sarcoids and 12 healthy skin s...
Miscellaneous Equine Liver Conditions. Miscellaneous equine liver conditions not covered in other chapters include chronic active hepatitis, Tyzzer's disease, seasonal idiopathic hepatitis, neoplasia, and idiopathic persistent hyperbilirubinemia. Chronic active hepatitis refers to inflammatory and fibrotic liver disease with an unknown cause. Treatment is aimed at reducing inflammation. Tyzzer's disease is caused by Clostridium piliforme infection and causes acute necrotizing hepatitis in foals. Successful treatment with antimicrobial therapy and supportive care is rare. Seasonal idiopathic hepatitis is a winter disease of Midweste...
Biliary Disorders in Horses. This review will mainly focus on the presentation, diagnosis, and treatment of cholangiohepatitis in adult horses. The condition is often accompanied by some degree of intrahepatic and/or extrahepatic biliary obstruction with "sludgy" bile or actual choleliths. In horses, these calculi are typically composed of calcium bilirubinate, rather than cholesterol. There is a propensity for cholangiohepatitis to become a recurrent, chronic condition and patient management should reflect this. Although much rarer, foreign body obstruction, neoplasia and, in some parts of the world, liver flukes can als...
Topical betulinic acid for treatment of equine melanoma and sarcoid. Betulinic acid, a natural pentacyclic triterpenoid, has demonstrated anti-inflammatory and anti-tumor properties in vitro, including activity against equine melanoma and sarcoid. However, there is limited in vivo evidence evaluating its clinical efficacy. The objective of this study was to assess the safety and efficacy of a compounded 1% betulinic acid cream for the treatment of equine cutaneous melanoma and sarcoid. Unassigned: This prospective, randomized, double-blinded, placebo-controlled clinical trial enrolled client-owned horses with melanoma or sarcoid tumors. Horses received either a...
Unusual, fatal neck cancer in a foal: immunohistological investigations and differential diagnosis. Neck masses may represent a diagnostic challenge for equine veterinarians, since they may involve different structures with a similar clinical appearance. Whereas neck masses in foals mostly result from non-neoplastic conditions, including various congenital abnormalities, neoplastic cervical masses have been rarely documented. This report describes the unusual case of a rapidly growing neck cancer in a four-month-old colt, resulting in a fatal outcome. Gross and immunohistological findings were most consistent with a poorly differentiated thymic carcinoma with sarcomatoid features and multifo...
Piezosurgical partial ostectomy of the incisive bone for an ossifying fibroma removal in a 4-year-old Warmblood gelding. Ossifying fibromas are uncommon in horses and complete surgical excision with premaxillectomy, maxillectomy or mandibulectomy is recommended. Piezosurgery has been previously used in equines only in one study. Objective: To report a case of ossifying fibroma treated with piezosurgery and to describe its follow-up. Methods: Clinical case report. Methods: A 4-year-old Zangersheide gelding was presented for a mass occupying the space of tooth 202. Histology confirmed the diagnosis of ossifying fibroma, which was removed by resection of soft tissues and a slice of the premaxilla with a piezotome. ...
Germline Pathogenic Variant in the APC Gene Suggestive of Gardner Syndrome in a Pony. A 12-year-old pony mare was presented for evaluation of dental disease and nasal discharge. At presentation, clinical signs included bilateral nasal discharge, cutaneous masses, and numerous hard enlargements involving the bones of the skull, maxilla, mandible, and cervical vertebrae. Oral exam revealed advanced dental disease with hard enlargements adjacent to and between numerous cheek teeth. Radiographs and computed tomography confirmed the presence of severe dental disease and proliferative bone lesions disseminated along the skull, hyoid apparatus, and cranial cervical vertebrae. The bony...
Integrative Phosphoproteomic Profiling Reveals Stage-Specific Signalling and Metabolism in Equine Melanocytic Neoplasm. Equine melanocytic neoplasms (EMN) are aggressive tumours characterised by high metastatic potential and limited therapeutic options available. However, the molecular mechanisms underlying their progression remain poorly understood. This study therefore presents the integrative phosphoproteomic analysis of EMN tissue, with the aim of elucidating stage-specific alterations in signalling pathways and metabolism. Nineteen tissue samples from grey horses were categorised as normal-stage (n = 6), early-stage EMN (n = 7), and severe-stage EMN (n = 6) and subjected to in-depth analysis us...
Radiation in Veterinary Practice: Paradigm Shift Toward Precision and Curative Approaches. Ionizing radiation therapy has undergone a clear paradigm shift in veterinary oncology and inflammatory disease management, moving from mainly palliative use toward structured, curative treatment programs. This review synthesizes current evidence on key modalities used in veterinary practice, including external beam radiotherapy, brachytherapy, systemic targeted radionuclide therapy, stereotactic radiosurgery, stereotactic body radiotherapy, radiosynoviorthesis, and low-dose radiotherapy. Each modality is discussed in relation to its physical and biological basis, major isotopes or beam types,...
Malignant Ovarian Teratoma in a Lusitano Filly: Diagnostic Challenges and Clinical Significance. An 8-month-old Lusitano filly (a young female horse) was referred with a five-day history of abdominal distension, respiratory distress, and hyporexia. Clinical and ultrasonographic examinations revealed ventral edema, anemia, leukocytosis, hypoalbuminemia, and bilateral pleural effusion. The filly subsequently developed progressive clinical deterioration, including persistent hyporexia, scant fecal output, and acute colic with nasogastric reflux, followed by sudden respiratory decompensation, collapse, and death. Post-mortem examination revealed a large, multilobulated abdominal mass involvin...
Cervical extradural mast cell tumour in a 2-year-old Irish Sport Horse colt. A 2-year-old Irish Sport Horse colt presented with acute, severe and rapidly progressive neurological signs, arriving recumbent to the hospital. Ante-mortem diagnostics did not reveal the cause of the recumbency, and the colt was euthanized after treatment and supportive care did not result in clinical improvement. A cranial cervical extradural mast cell tumour with eosinophilic granulomas and secondary compressive myelopathy with axonal degeneration was diagnosed on post-mortem evaluation. No other masses or clinically relevant findings were present, suggesting a primary neoplasm. Neoplasia a...
Metastatic adenocarcinoma in the parotid gland in a horse – clinical and pathological findings. This case report details the findings of a metastatic adenocarcinoma of the parotid gland, a rare neoplasm in horses with limited treatment options. A 12-year-old, Criollo breed, gelding was presented with an enlarged left parotid gland that had been previously treated for 6 months without response to treatment. Based on the results of the diagnostic procedures performed, the horse underwent a total sialadenectomy and died of hypovolemic shock in the recovery room. Post-mortem examination revealed metastatic neoplastic infiltration of the submandibular lymph nodes and the lymphatic network at ...
Multicentric Malignant Melanoma in a Grey Mare: A Case Report. Grey coat color in horses, resulting from a 4.6 kb copy number variation (CNV) within the syntaxin 17 (STX17) gene (Grey locus), is linked to progressive hair depigmentation and a markedly increased risk of melanoma, likely to its function as a melanocyte-specific enhancer. Objective: This report details the clinical, pathological, and genomic findings of a 26-year-old flea-bitten grey mare with multiple melanocytic tumors, progressive dyspnea, and congestive heart failure. Due to the poor prognosis the horse was euthanized and submitted for necropsy to the Long Island University - Lewyt Colle...
Spontaneous regression of equine sarcoids is an exceptional event. Sarcoids are benign, yet locally aggressive skin tumours that commonly affect horses and other equid species. The lesions are induced by bovine papillomavirus types 1, 2, and probably 13 in conjunction with other factors including trauma and a genetic predisposition. Although sarcoids have a substantial impact on the health and welfare of affected equids, information on the immune response to bovine papillomavirus infection and resulting sarcoids is limited. However, there is evidence that sarcoid disease is associated with an impaired immune response to bovine papillomavirus infection. This o...
Equine Corneal Stromal Invasive Squamous Cell Carcinoma: Clinical and in Vivo Confocal Microscopic Features of 7 Cases. To describe the clinical and in vivo confocal microscopy (IVCM) characteristics of horses with corneal stromal invasive squamous cell carcinoma (CSI-SCC). Methods: Retrospective study of 7 horses with histopathologically confirmed unilateral CSI-SCC. Methods: Horses with corneal CSI-SCC were examined by laser scanning IVCM. Signalment, clinical findings, and histopathology results were compared with IVCM findings. Results: Clinical ocular lesions in all horses included a heavily vascularized, opaque, gray or tan, anterior or midstromal opacity invading the cornea from the limbus. The corneal ...
Hemithyroidectomy due to a large, solid follicular thyroid adenoma in a 19-year-old thoroughbred mare. This case report describes the successful hemithyroidectomy of the largest equine solid follicular adenoma described in the veterinary literature to date. A 19-year-old thoroughbred mare was referred to Oakhill Veterinary Centre for the surgical removal of a large, left-sided thyroid gland measuring 26cm in diameter. Pre-operative considerations, the hemithyroidectomy surgical technique as well as the intra- and post-operative complications encountered, are discussed. Following surgery the horse had no long-term complications and continues to thrive four and a half years post-operatively.
