Pleomorphic corneal sarcoma resembling malignant peripheral nerve sheath tumor in a horse.
Authors: Kappe E C, Köhler K, Felbert I V, Teifke J P, Tóth J, Reinacher M
Journal: Veterinary pathology
Summary
# Editorial Summary A 14-year-old Haflinger gelding presented with a corneal mass that prompted surgical resection and comprehensive pathological examination, representing a rare opportunity to characterise mesenchymal neoplasia in equine ocular tissue. Histopathological and immunohistochemical analysis revealed pleomorphic spindle-cell architecture with immunophenotypic features consistent with malignant peripheral nerve sheath tumour (MPNST) rather than the initially suspected fibrosarcoma, though the precise mesenchymal origin remained ambiguous. Testing ruled out bovine papillomavirus infection as an aetiological agent, leaving the tumour's aetiology undetermined. Since corneal mesenchymal tumours are exceptionally uncommon in both human and veterinary medicine, this case expands the diagnostic differential for periocular masses and highlights the diagnostic value of immunohistochemistry in clarifying neoplastic cell lineage when standard histology proves equivocal. Equine practitioners should consider MPNST among differential diagnoses for protruding corneal lesions, particularly when morphology is inconsistent with more typical presentations, and understand that immunophenotypic profiling may be essential for definitive classification and subsequent prognostic guidance.
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Practical Takeaways
- •Any protruding corneal mass in a horse requires surgical resection and histopathologic examination, as corneal sarcomas, though rare, can occur and may be malignant.
- •Mesenchymal corneal neoplasms should be on the differential diagnosis for chronic or progressive corneal swelling and mass formation unresponsive to standard therapy.
- •Complete surgical removal and tissue diagnosis are essential for determining prognosis and appropriate management strategy.
Key Findings
- •A 14-year-old Haflinger gelding presented with a protruding corneal mass that was resected and histopathologically diagnosed as corneal sarcoma, most consistent with malignant peripheral nerve sheath tumor.
- •Immunohistochemical examination confirmed mesenchymal origin of neoplastic cells.
- •Corneal mesenchymal neoplasms are extremely uncommon in horses and other domestic animals.
- •Bovine papillomavirus infection was not detected as a causative agent.