Equine maxillofacial intraosseous cystic lesions: a retrospective study of 17 cases.
Abstract: Cystic and pseudocystic masses of the equine maxilla and mandible are rare lesions that result in clinically significant morbidity and/or mortality for the patient. Previous literature consists of case reports or case series. Few studies have addressed the variety of cystic lesions and comparative features. The aim of this study was to retrospectively describe the clinical signs, imaging findings, histopathologic diagnoses, treatments, and clinical outcomes for cystic masses in the equine maxilla and mandible. Unassigned: Cases were recruited from six sources including a pathology laboratory, universities, and multiple private practices. Inclusion criteria were cystic/cavitated lesions within the maxilla mandible, and/or incisive bones that had a complete medical record that included history, gross appearance of the mass, diagnostic imaging, histopathology report, treatments performed, and clinical outcomes. Primary sinus cysts and teratomas were excluded from the study. Unassigned: Lesions were identified in 17 patients with 1 patient having multifocal maxillomandibular cystic lesions. The most common lesion location was the body of the mandible. Diagnosis of lesion etiology and type was made by assimilating histopathology with clinical findings and imaging results. The following cysts were diagnosed: dentigerous cyst (6), bone cyst (6), and radicular cyst (3). Two lesions were unclassified, radiolucent inflammatory lesions. Patients were treated surgically with marginal excision and/or aggressive cyst lining debridement for 16/17 cases with rostral mandibulectomy performed in 1/17 cases. Excisional biopsies were performed at the time of definitive surgery for 12/17 cases, which resulted in histopathologic diagnoses. Follow-up ranged from 0 to 872 days postoperatively with a mean of 200 days with only 1 case having no follow-up. Eleven out of 17 cases (64.7%) had no documented recurrence following surgical excision. The overall complication rate was 35.3% (6/17 cases) and included orofacial/oroantral fistula formation, sinus flap suture reaction, and sinus flap mycosis. Unassigned: Diagnosis and treatment of equine cystic masses of the maxilla, mandible, and/or incisive bones were greatly aided by assimilating oral exam and diagnostic imaging findings with histopathologic results.
Copyright © 2025 Kelley, Rawlinson and Bell.
Publication Date: 2025-09-10 PubMed ID: 41001063PubMed Central: PMC12457172DOI: 10.3389/fvets.2025.1644866Google Scholar: Lookup
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Summary
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Overview
- This study retrospectively analyzed 17 cases of cystic lesions within the jaw bones of horses, describing their clinical signs, diagnosis, treatment, and outcomes to improve understanding and management of these rare but clinically significant masses.
Background and Purpose
- Cystic and pseudocystic masses in the equine maxilla (upper jaw) and mandible (lower jaw) are uncommon.
- These lesions can cause serious health problems or death in affected horses.
- Earlier reports mainly focused on individual cases or small series without broad comparison or analysis.
- The study aimed to provide a more comprehensive retrospective description concerning:
- Clinical signs presented by horses
- Imaging findings (such as radiographs)
- Histopathology diagnoses (microscopic examination of tissue samples)
- Treatments applied
- Long-term clinical outcomes after treatment
Methods
- Cases were gathered from multiple sources: a pathology laboratory, universities, and private veterinary practices.
- Inclusion criteria:
- Cystic or cavitated lesions located within the maxilla, mandible, or incisive bones
- Complete medical records including history, gross lesion appearance, diagnostic imaging, histopathology report, treatment details, and follow-up outcomes
- Excluded conditions: primary sinus cysts and teratomas (types of growths with distinct origin or nature)
Findings
- Identified a total of 17 affected horses, with one horse having multiple cystic lesions.
- The most common affected site was the body of the mandible.
- Diagnoses were made by integrating clinical symptoms, imaging, and histopathological results.
- Types of cystic lesions diagnosed:
- Dentigerous cysts (6 cases) – cysts associated with teeth development
- Bone cysts (6 cases) – cystic lesions within the bony tissue
- Radicular cysts (3 cases) – cysts at the root of a tooth
- Two unclassified lesions described as radiolucent inflammatory lesions, meaning they appeared as areas with lower density on imaging due to inflammation
Treatment
- Surgical intervention was performed in 16 out of 17 cases, primarily involving:
- Marginal excision – removing the lesion with a small margin of healthy tissue
- Aggressive debridement – thorough removal of cyst lining
- One case required rostral mandibulectomy, which is removal of the front portion of the lower jaw.
- Excisional biopsies (removing and examining the lesion) were done in 12 cases concurrently with surgery for definitive diagnosis.
Outcomes and Follow-Up
- Follow-up durations varied widely, from none to 872 days post-surgery, with an average of around 200 days.
- Majority of cases (11 out of 17, 64.7%) showed no recurrence of cysts after surgical treatment.
- Complication rate was 35.3% (6 out of 17 cases) with issues including:
- Fistula formation between oral cavity and facial or sinus areas.
- Sinus flap suture reaction – negative tissue response to stitches.
- Sinus flap mycosis – fungal infection in the surgical site.
Conclusions and Clinical Significance
- Accurate diagnosis and effective treatment of maxillofacial intraosseous cystic lesions in horses are enhanced by combining:
- Detailed oral examination
- Diagnostic imaging (e.g., radiographs)
- Histopathologic examination of the lesion tissue
- Surgical excision with or without cyst lining removal appears to be effective in resolving these lesions in a majority of cases.
- Awareness of potential complications is important for postoperative management and prognosis.
- This study adds valuable comparative data to a field previously limited to case reports, aiding veterinary practitioners in diagnosing and planning treatment for equine cystic jaw lesions.
Cite This Article
APA
Kelley JL, Rawlinson JE, Bell CM.
(2025).
Equine maxillofacial intraosseous cystic lesions: a retrospective study of 17 cases.
Front Vet Sci, 12, 1644866.
https://doi.org/10.3389/fvets.2025.1644866 Publication
Researcher Affiliations
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States.
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States.
- Specialty Oral Pathology for Animals (SOPA), Geneseo, IL, United States.
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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