Squamous cell carcinoma of the hoof wall in a stallion.
Authors: Berry, O'Brien, Pool
Journal: Journal of the American Veterinary Medical Association
Summary
# Editorial Summary: Squamous Cell Carcinoma of the Hoof Wall A 15-year-old Thoroughbred stallion presented with chronic low-grade lameness and a non-painful sessile mass on the dorsal hoof wall, which radiography suggested was a benign keratoma based on the characteristic circular lucency visible within the distal phalanx. Surgical removal was delayed ten months following initial presentation, at which point histopathological examination revealed the lesion to be squamous cell carcinoma rather than the suspected benign condition—a critical misdiagnosis with significant consequences. Despite surgical intervention, the tumour progressed aggressively and invaded deeply into the distal phalanx, ultimately resulting in a pathological articular fracture within eight months post-operatively. This case underscores the dangers of relying solely on clinical appearance and radiographic findings to differentiate between benign keratomas and malignant squamous cell carcinomas of the hoof wall, as both may present with seemingly identical features. For practitioners managing hoof wall masses, obtaining definitive histological diagnosis through biopsy before commencing treatment is essential, as delayed recognition of malignancy not only compromises prognosis but may also permit tumour progression that renders conservative farriery management impossible and necessitates more extensive surgical intervention or limb salvage decisions.
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Practical Takeaways
- •Any chronic hoof wall mass with lameness warrants biopsy and histologic examination, even if radiographic appearance suggests benign keratoma—do not assume benign based on imaging alone.
- •Squamous cell carcinoma of the hoof can progress rapidly to involve articular structures; early accurate diagnosis improves treatment planning and prognosis discussion with owners.
- •Farriers and veterinarians should maintain a high index of suspicion for malignancy when presented with non-sensitive hoof wall masses and chronic unexplained lameness, and refer for tissue diagnosis promptly.
Key Findings
- •Squamous cell carcinoma of the hoof wall can mimic benign keratoma on radiographic examination, presenting as a well-circumscribed circular lucency in the distal phalanx.
- •A 15-year-old Thoroughbred stallion with a sessile dorsal hoof wall mass and chronic grade 2/5 lameness was initially suspected to have keratoma but was confirmed as squamous cell carcinoma on histology.
- •Progressive tumor invasion resulted in pathologic articular fracture of the distal phalanx 8 months post-surgery, demonstrating the aggressive nature of this malignancy.
- •Histologic diagnosis is essential to differentiate between benign and malignant hoof wall masses, as clinical and radiographic features alone may be misleading.