Hypertrophic osteopathy and dysgerminoma in a mare

Area of Science:

• Veterinary medicine
• Equine oncology
• Pathology

Background:

• Hypertrophic osteopathy (HO) is a rare condition characterized by new bone formation, often associated with intrathoracic or abdominal disease.
• This case details a mare with clinical signs suggestive of HO and subsequent diagnostic findings.

Observation:

• The mare exhibited chronic abdominal discomfort and noticeable bony swellings in the pastern regions of both forelegs.
• Diagnostic imaging and histopathology revealed a dysgerminoma of the left ovary with extensive metastasis.

Findings:

• The ovarian dysgerminoma had metastasized to abdominal lymph nodes and infiltrated the posterior vena cava.
• While gross thoracic lesions were absent, microscopic examination confirmed tumor metastasis within pulmonary arterioles.

Implications:

• This case highlights the potential link between ovarian dysgerminoma and hypertrophic osteopathy in horses.
• It underscores the importance of thorough diagnostic investigation for abdominal masses in horses presenting with peripheral bony changes.