The research describes a case of localized amyloidosis – an uncommon disease characterized by abnormal protein deposits – found in the nasal, conjunctival, and corneal tissues of a 15-year-old horse. This resulted in nasal and conjunctival masses and severe breathing difficulties. The researchers identified the presence of abundant amyloid deposits, suggestive of AL amyloidosis. Despite initial surgical intervention that alleviated symptoms, the masses returned, leading to recurring respiratory blocks indicating the progressive nature of this disease.

Objective of the Research

• The objective of this study was to diagnose and understand the development and progression of localized amyloidosis in the nasal and ocular regions of a 15-year-old pony.

Procedure and Findings

• A surgical procedure was carried out to relieve the pony of large nasal and conjunctival masses causing severe dyspnoea and exercise intolerance.
• Post-surgery, histological examination indicated the presence of large amounts of extracellular, eosinophilic material in the nasal mucosa indicating potential localized nasal amyloidosis.
• Despite initial relief, the nasal masses recurred and additional conjunctival masses developed, leading to the pony’s euthanasia.
• Necropsy revealed the presence of rubbery, grey to yellow tissue masses in the nasal and conjunctival regions, infiltrating and expanding the cornea.
• Microscopic examination confirmed abundant deposits of non-branching fibrils consistent with amyloid in the nasal mucosa and cornea.
• Through Immunohistochemistry, no labelling for AA amyloid, or peptides for serum amyloid A were identified, however, peptides consistent with immunoglobulin kappa-like light chains were detected, indicative of possible AL amyloidosis.

Conclusions

• The research observed a case of localized nasal and conjunctival amyloidosis in a single pony – a condition that has only been reported in seven cases before, this being the first case of combined nasal and corneal amyloidosis.
• Surgical intervention initially led to clinical improvement, however, the case exhibited a rapid recurrence and progression of the disease, resulting in the involvement of ocular tissues and recurrent respiratory obstruction.

Implications

• The research provides vital insights into the nature and progression of localized amyloidosis involving nasal and ocular regions in horses.
• It highlights the need for further research to better understand this rare condition and develop effective treatments for long-term management.