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Frontiers in veterinary science2025; 12; 1689782; doi: 10.3389/fvets.2025.1689782

Granulosa cell tumor in Arabian mares: prevalence, risk factors, clinical and histopathological findings and outcome of surgical removal.

Abstract: Granulosa cell tumors (GCTs) represent the most common ovarian neoplasms in mares, yet data on their epidemiology, risk factors, and clinical outcomes in Arabian horses are limited. Understanding their prevalence and diagnostic features is crucial for improving fertility management in this breed. Unassigned: Clinical records from 807 Arabian mares housed on 35 stud farms in central Saudi Arabia were retrospectively reviewed to determine the prevalence of GCT and potential risk factors, including age, parity, and anabolic steroid use. Twenty-four confirmed cases were further investigated using clinical examination, ultrasonography, endocrine profiling, and histopathology. Surgical management by unilateral ovariectomy was performed in 20 mares, and postoperative fertility outcomes were documented. Unassigned: The overall prevalence of GCT was 0.6%. Logistic regression analysis identified anabolic steroid use as a significant risk factor (Odds Ratio = 13.21,  = 0.0001). Stallion-like behavior was the most frequent clinical manifestation (58.3%), followed by anestrus (33.3%) and persistent estrus (8.3%). Ultrasonography revealed four distinct tumor morphologies, with contralateral ovarian atrophy present in 75% of cases. Histopathology classified tumors into adult type (76.5%) and juvenile type (23.5%). Preoperative testosterone concentrations were elevated and decreased postoperatively in 72.7% of mares. Ovariectomy resulted in an 80% recovery rate, with 68.8% of mares regaining fertility. Unassigned: This study demonstrates that anabolic steroid administration markedly increases the risk of GCT in Arabian mares. Behavioral changes, ultrasonographic appearance, and hormonal profiles remain key diagnostic indicators, while histopathology confirms tumor classification. Surgical excision proved effective, with favorable fertility outcomes in most mares. These findings underscore the importance of early diagnosis and highlight the need for judicious use of anabolic steroids in breeding programs.
Copyright © 2025 Derar, Ali, Al-Sobayil and Refaai.
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Publication Date: 2025-11-13 PubMed ID: 41321570PubMed Central: PMC12659192DOI: 10.3389/fvets.2025.1689782Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This research investigates the prevalence, risk factors, clinical features, and outcomes of granulosa cell tumors (GCTs) in Arabian mares, focusing on their diagnosis and treatment effects on fertility.

Introduction and Context

  • Granulosa cell tumors (GCTs) are the most common ovarian tumors diagnosed in mares.
  • There is limited data specifically about GCTs in Arabian mares, which is important because breed-specific information can improve diagnosis and management.
  • This study is motivated by the need to understand how often these tumors occur, what factors contribute to their development, how they present clinically, and how they respond to treatment in Arabian horses.

Study Design and Methodology

  • Retrospective review of clinical records from 807 Arabian mares kept on 35 stud farms in central Saudi Arabia.
  • Analysis included evaluation of potential risk factors such as age, parity (number of pregnancies), and anabolic steroid use.
  • 24 mares with confirmed GCT diagnosis underwent additional detailed evaluation:
    • Clinical examination for behavioral and reproductive signs.
    • Ultrasonography to study tumor features and ovarian condition.
    • Endocrine profiling measuring hormone levels, especially testosterone.
    • Histopathological examination for tumor classification.
  • Surgical treatment involved unilateral ovariectomy (removal of one ovary) in 20 mares.
  • Fertility outcomes were monitored after surgery to assess effectiveness.

Key Findings

  • The overall prevalence of GCT in the sampled population was low at 0.6%.
  • Use of anabolic steroids was a significant risk factor, increasing the risk over 13-fold.
  • Common clinical signs included:
    • “Stallion-like” behavior in over half of the cases (58.3%), indicating hormonal influence affecting behavior.
    • Anestrus (absence of estrus cycles) in about one-third (33.3%).
    • Persistent estrus (long-lasting heat behavior) in a smaller number (8.3%).
  • Ultrasonographic examination identified four types of tumor morphologies and showed that 75% of cases had atrophy of the ovary opposite to the tumor.
  • Histopathology divided tumors into 2 categories:
    • Adult type (76.5%)
    • Juvenile type (23.5%)
  • Preoperative testosterone levels were elevated; postoperatively, testosterone decreased in nearly three-quarters (72.7%) of mares.
  • Surgical removal of the affected ovary led to an 80% recovery rate, with 68.8% regaining fertility afterward.

Implications and Conclusions

  • Anabolic steroid administration significantly increases the likelihood of developing GCT in Arabian mares, highlighting a key modifiable risk factor.
  • Clinical behavior changes like stallion-like behavior, ultrasonographic tumor features, and hormonal profiles serve as important diagnostic tools before surgery.
  • Histopathology is essential for confirming tumor type and guiding prognosis.
  • Unilateral ovariectomy is an effective treatment, with a good proportion of mares recovering fertility post-surgery, supporting surgical intervention as a beneficial management strategy.
  • Early diagnosis using clinical, imaging, and hormonal assessment is crucial for optimal outcomes.
  • The study recommends careful use of anabolic steroids in breeding programs to reduce tumor risk and preserve reproductive health.

Cite This Article

APA
Derar D, Ali A, Al-Sobayil F, Refaai W. (2025). Granulosa cell tumor in Arabian mares: prevalence, risk factors, clinical and histopathological findings and outcome of surgical removal. Front Vet Sci, 12, 1689782. https://doi.org/10.3389/fvets.2025.1689782

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 12
Pages: 1689782
PII: 1689782

Researcher Affiliations

Derar, Derar
  • Department of Clinical Sciences, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia.
Ali, Ahmed
  • Department of Clinical Sciences, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia.
Al-Sobayil, Fahd
  • Department of Clinical Sciences, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia.
Refaai, Walid
  • Department of Surgery, Anesthesiology and Radiology, University Veterinary Hospital, Qassim University, Buraidah, Saudi Arabia.
  • Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig-City, El Sharkia, Egypt.

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.

References

This article includes 38 references
  1. McCue PM, Roser JF, Munro CJ, Liu IK, Lasley BL. Granulosa cell tumors of the equine ovary. Vet Clin North Am Equine Pract (2006) 22:799–817.
    doi: 10.1016/j.cveq.2006.08.002pubmed: 17129804google scholar: lookup
  2. Crabtree J. Review of seven cases of granulosa cell tumour of the equine ovary. Vet Rec (2011) 169:251.
    pubmed: 21832000
  3. Ali A, Alamaary M, Al-Sobayil F, Mehana E, Fathy A. Ovarian tumours in Arabian mares. Comp Clin Pathol (2015) 24:157–62.
    doi: 10.1007/s00580-013-1877-3google scholar: lookup
  4. Sherlock CE, Lott-Ellis K, Bergren A, Withers JM, Fews D, Mair TS. Granulosa cell tumours in the mare: a review of 52 cases. Equine Vet Educ (2016) 28:75–82.
    doi: 10.1111/eve.12449google scholar: lookup
  5. Tsogtgerel M, Tagami M, Watanabe K, Murase H, Hirosawa Y, Kobayashi Y. Case report: the case of a 17 kg ovarian granulosa cell tumor in a Breton draft mare. J Equine Sci (2021) 32:67–72.
    doi: 10.1294/jes.32.67pmc: PMC8240524pubmed: 34220274google scholar: lookup
  6. Bailey CS, Macpherson ML, Pozor MA, Benson S, Troedsson MHT, McCue PM. Granulosa-theca cell tumors in mares: a review of clinical, hormonal, and ultrasonographic features. J Equine Vet Sci (2020) 85:102890.
    doi: 10.1016/j.jevs.2019.102890google scholar: lookup
  7. Hinrichs K. Reproductive disorders in mares: ovarian tumors and their management. Theriogenology (2021) 166:34–42.
    doi: 10.1016/j.theriogenology.2021.02.005google scholar: lookup
  8. Yoshida G, Tsunoda N, Miyake YI, Shafiqul HMD, Osawa T, Nagamine N. Endocrinological studies of mares with granulosa-theca cell tumor. J Equine Sci (2000) 11:35–43.
    doi: 10.1294/jes.11.35google scholar: lookup
  9. Ball BA, Conley AJ, MacLaughlin DT, Grundy SA, Sabeur K, Liu IK. Expression of anti-Müllerian hormone (AMH) in equine granulosa-cell tumors and in normal equine ovaries. Theriogenology (2008) 70:968–77.
    doi: 10.1016/j.theriogenology.2008.06.008pubmed: 18599114google scholar: lookup
  10. Almeida J, Ball BA, Conley AJ, Place NJ, Liu IK, Scholtz EL. Biological and clinical significance of anti-Müllerian hormone determination in blood serum of the mare. Theriogenology (2011) 76:1393–402.
    doi: 10.1016/j.theriogenology.2011.06.022pubmed: 21798581google scholar: lookup
  11. Nelissen S, Miller AD. Comparison of anti-Müllerian hormone and inhibin immunolabeling in canine and equine granulosa cell tumors. J Vet Diagn Invest (2022) 34:1027–31.
    doi: 10.1177/10406387221124589pmc: PMC9597338pubmed: 36113168google scholar: lookup
  12. Bailey MT, Troedsson MH, Wheato JE. Inhibin concentrations in mares with granulosa cell tumors. Theriogenology (2002) 57:1885–95.
    doi: 10.1016/S0093-691X(02)00657-2pubmed: 12041692google scholar: lookup
  13. Huggins L, Norris J, Conley A, Dini P. Abnormal mare behaviour is rarely associated with changes in hormonal markers of granulosa cell tumours: a retrospective study. Equine Vet J (2023) 56:759–67.
    doi: 10.1111/evj.13967pubmed: 37344926google scholar: lookup
  14. Turner RM, McCue PM, Scoggin KE. Ultrasonographic features of granulosa cell tumors in mares. Vet Radiol Ultrasound (2020) 61:456–63.
    doi: 10.1111/vru.12848google scholar: lookup
  15. Korany RMS, Derbala MK, Mosallam TE, Fadel M, Aly AH, Essmail ME. Diagnosis of granulosa cell tumors in Arabian mares by ultrasonography, hormonal profile and histopathology. Adv Anim Vet Sci (2020) 8:327–32.
    doi: 10.17582/journal.aavs/2020/8.3.327.332google scholar: lookup
  16. Ball BA, Almeida J, Conley AJ. Determination of serum anti-Müllerian hormone for the diagnosis of granulosa-cell tumours in mares.. Equine Vet J (2013) 45:199–203.
    doi: 10.1111/j.2042-3306.2012.00631.xpubmed: 22779762google scholar: lookup
  17. Renaudin CD, Kelleman AA, Keel K, McCracken JL, Ball BA, Ferris RA. Equine granulosa cell tumours among other ovarian conditions: diagnostic challenges.. Equine Vet J (2021) 53:60–70.
    doi: 10.1111/evj.13279pubmed: 32391939google scholar: lookup
  18. Ellenberger C, Bartmann CP, Hoppen HO, Kratzsch J, Aupperle H, Klug E. Histomorphological and immunohistochemical characterization of equine granulosa cell tumours.. J Comp Pathol (2007) 136:167–76.
    doi: 10.1016/j.jcpa.2006.12.001pubmed: 17416235google scholar: lookup
  19. Ball BA, Scoggin KE, Troedsson MHT, Conley AJ. Equine ovarian tumors: histopathological classification and prognostic indicators.. Vet Pathol (2022) 59:210–25.
    doi: 10.1177/03009858211055505google scholar: lookup
  20. Riman T, Dickman PW, Nilsson S, Correia N, Nordlinder H, Magnusson CM. Risk factors for epithelial borderline ovarian tumors: results of a Swedish case-control study.. Gynecol Oncol (2001) 83:575–85.
    doi: 10.1006/gyno.2001.6451pubmed: 11733975google scholar: lookup
  21. Young AC, Vick MM, Wooldridge AA, Boakari YL. Anabolic steroids as a risk factor for granulosa cell tumors in mares: a retrospective study.. J Vet Intern Med (2021) 35:1892–8.
    doi: 10.1111/jvim.16183google scholar: lookup
  22. Bancroft JD, Stevens A. Theory and practice of histological techniques. 6th ed. London: Churchill Livingstone; (2008).
  23. Frederico LM, Gerard MP, Pinto CR, Gradil CM. Bilateral occurrence of granulosa-theca cell tumors in an Arabian mare.. Can Vet J (2007) 48:502–5.
    pmc: PMC1852596pubmed: 17542368
  24. Knowles EJ, Tremaine WH, Pearson GR, Mair TS. A database survey of equine tumours in the United Kingdom.. Equine Vet J (2015) 48:280–4.
    doi: 10.1111/evj.12421pubmed: 25594351google scholar: lookup
  25. McCue PM, Roser JF. Granulosa cell tumors in the mare: a review of current knowledge.. J Equine Vet Sci (2019) 72:1–7.
    doi: 10.1016/j.jevs.2018.10.014google scholar: lookup
  26. Hoque S, Derar RI, Osawa T, Taya K, Watanabe G, Miyake Y. Spontaneous repair of the atrophic contralateral ovary without ovariectomy in the case of a granulosa theca cell tumor (GTCT) affected mare.. J Vet Med Sci (2003) 65:749–51.
    doi: 10.1292/jvms.65.749pubmed: 12867740google scholar: lookup
  27. Hultgren BD, Zack PM, Pearson EG, Kaneps AJ. Juvenile granulosa cell tumour in an equine weanling.. J Comp Pathol (1987) 97:137–42.
    doi: 10.1016/0021-9975(87)90026-3pubmed: 3597846google scholar: lookup
  28. Derar R, Ali A, Fathy A, Al-Sobayil A, Al-Hawas A. Resumption of the follicular activity of the contra-lateral ovary following surgical removal of a granulosa cell tumor in the right ovary in a 19-year-old Arabian mare.. J Agric Vet Sci (Qassim Univ) (2018) 11:103–8.
  29. Drozdzewska K, Gehlen H. Markers for internal neoplasia in the horse.. Vet Med Sci (2023) 9:132–43.
    doi: 10.1002/vms3.1042pmc: PMC9857019pubmed: 36495211google scholar: lookup
  30. Dolin A, Schweiger P, Waselau M, Egerbacher M, Walter I. Immunohistochemical markers for equine granulosa cell tumors: a pilot study.. J Equine Sci (2023) 34:37–46.
    doi: 10.1294/jes.34.37pmc: PMC10315638pubmed: 37405069google scholar: lookup
  31. Zhang Y, Wang Y, Gu Y, Liu Y, Liu G, Wu J. Regulation of FOXL2 gene in ovarian granulosa cell tumor by JNK inhibitor. Sci Rep (2025) 15:12167.
    doi: 10.1038/s41598-025-85439-8pmc: PMC11982297pubmed: 40204754google scholar: lookup
  32. Stabenfeldt GH, Hughes JP, Kennedy PC, Meagher DM. Hormonal profiles in mares with granulosa-theca cell tumors. Domest Anim Endocrinol (2021) 74:106502.
    doi: 10.1016/j.domaniend.2020.106502google scholar: lookup
  33. Daniel AJ, Easley JT, Story MR, Hendrickson DA, Hackett ES. Standing laparoscopic removal of large granulosa cell tumours using a specimen retrieval bag and morcellator. Equine Vet Educ (2015) 27:505–9.
    doi: 10.1111/eve.12280google scholar: lookup
  34. Watson ED, Sertich PL. Post-surgical fertility in mares following granulosa cell tumor removal. Equine Vet J (2022) 54:389–95.
    doi: 10.1111/evj.13446google scholar: lookup
  35. Alexander GR, Tweedie MA, Lescun TB, McKinnon AO. Haemoperitoneum secondary to granulosa cell tumour in two mares. Aust Vet J (2004) 82:481–4.
    doi: 10.1111/j.1751-0813.2004.tb11176.xpubmed: 15359963google scholar: lookup
  36. Dubuisson J, Botchorishvili R, Perrette S, Bourdel N, Jardon K, Rabischong B. Incidence of intraabdominal adhesions in a continuous series of 1000 laparoscopic procedures. Am J Obstet Gynecol (2010) 203:111.e1–3.
    doi: 10.1016/j.ajog.2010.04.019pubmed: 20537306google scholar: lookup
  37. Tommasa SD, Roth SP, Triebe T, Brehm W, Lohmann KL, Stöckle SD. Successful intra-abdominal resection of a 24 kg ovarian granulosa cell tumor in a warmblood mare. Open Vet J (2023) 13:1212–8.
    doi: 10.5455/OVJ.2023.v13.i9.17pmc: PMC10576582pubmed: 37842112google scholar: lookup
  38. Hubert JD, Burba DJ, Moore RM. Evaluation of a vessel sealing device for laparoscopic granulosa cell tumor removal in standing mares. Vet Surg (2006) 35:324–9.
    doi: 10.1111/j.1532-950X.2006.00152.xpubmed: 16756611google scholar: lookup

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