Equine Hoof Canker: Cell Proliferation and Morphology.
Authors: Apprich V, Licka T, Zipfl N, Tichy A, Gabriel C
Journal: Veterinary pathology
Summary
# Editorial Summary: Equine Hoof Canker Cell Proliferation and Morphology Apprich et al. (2017) challenged the long-held assumption that hoof canker results primarily from excessive cell proliferation in the dermal papillary body, instead using immunohistochemistry to examine proliferation markers and tissue morphology in surgically removed canker tissue from 19 affected horses compared with healthy control hooves. Whilst canker tissue displayed striking histological features—including lacunae, vacuoles, giant cells, haemorrhage, and inflammation alongside an unusual koilocytotic appearance in keratinocytes—fibroblast proliferation rates remained similarly low (<3%) in both diseased and healthy tissue, contradicting the classical description of this condition. Elevated PCNA protein expression in keratinocytes and fibroblasts, however, pointed to dysregulation of normal keratinocyte differentiation rather than uncontrolled proliferation as the primary pathological mechanism. This distinction has meaningful implications for how farriers, veterinarians, and rehabilitation specialists approach canker management: rather than viewing the condition purely as overproliferation requiring aggressive tissue removal, understanding it as a differentiation disorder opens the door to exploring treatments targeting keratinocyte maturation and epidermal cornification. The findings suggest that successful long-term management may depend less on reducing tissue growth and more on restoring normal keratinisation pathways within the hoof dermis.
Read the full abstract on PubMed
Practical Takeaways
- •Hoof canker is fundamentally a problem of abnormal skin cell maturation rather than excessive growth—this changes how we think about treatment targets and prognosis.
- •The presence of koilocytotic keratinocytes and morphological disruption suggests investigating infectious (possibly viral) or metabolic triggers rather than focusing solely on managing proliferation.
- •Surgical removal of diseased tissue remains indicated, as the pathology involves loss of normal cornification and structural integrity that conservative management alone cannot restore.
Key Findings
- •Canker tissue showed 5 major morphological alterations (lacunae, vacuoles, giant cells, hemorrhage, inflammation) not present in healthy hooves.
- •Increased PCNA protein expression in keratinocytes and fibroblasts of canker tissue compared to control tissue.
- •Ki67 levels were actually higher in control keratinocytes than canker tissue, contradicting previous assumptions of increased dermal papillary proliferation.
- •Dysregulation of keratinocyte differentiation, not excessive cell proliferation, appears to be the key pathological mechanism in hoof canker.