Vascular hamartoma as the cause of hind limb lameness in a horse.

This study reports a case of a rare benign tumor found in the hind limb of a 5-year-old gelding horse, indicating that such a growth can be a cause of lameness.

Introduction and Case Report

• The researchers share an uncommon case of a 5-year-old gelding horse with limb lameness caused by a benign tumor, also known as a vascular hamartoma.
• The proposed tumor, present for 2 months, was found in the subcutis of the horse’s hind limb and incited lameness.
• Despite the tumor, the horse’s vital signs were reported as common on physical examination and laboratory results were within standard boundaries, showing no systemic effects derived from the tumor.

Investigative Measures

• To identify the cause of lameness, a radiographic examination of the affected region was conducted; however, no anomalies in the bone structure were found, pointing to superficial or tissue-related causes.
• The researchers also performed an aspiration procedure in which bloody fluid was extracted. This pointed towards a vascular or blood-related issue.

Surgical Intervention and Findings

• An I-shaped skin incision was made and the tumor was excised, or removed, in its entirety (en-block).
• The removed tumor was then studied at a microscopic level.
• It was found to be a vascular hamartoma, a seldom-seen type of benign tumor characterized by cavernous haemangiomatous tissue, which essentially is a benign tumor composed of blood vessels, and a proliferation of multiple vessels of variable diameter.

Importance and Conclusions

• The report underscores the importance of considering a limb vascular hamartoma as an occasional lesion in the differential diagnosis of lameness in horses.
• This means that while the occurrence is not frequent, practitioners should consider the possibility of a vascular hamartoma when determining the cause of lameness in a horse, as one of several potential diagnoses.