Cutaneous epitheliotropic T-cell lymphoma in a donkey - a case report.
Authors: Kondratjeva Jevgenija, Julien Florie, Coutelier Céline, Humeau Louis, Moog Fabien, Combarros Daniel, Fourquaux Isabelle, Pressanti Charline, Delverdier Maxence, Moore Peter F, Cadiergues Marie Christine
Journal: BMC veterinary research
Summary
# Editorial Summary: Cutaneous Epitheliotropic T-cell Lymphoma in Donkeys Cutaneous epitheliotropic T-cell lymphoma, commonly known as mycosis fungoides, is a rare malignant skin tumour with established occurrence in horses, dogs, cats, and humans—yet this case report documents the first confirmed diagnosis in a donkey, expanding our understanding of species susceptibility. The diagnostic approach combined routine clinical and histopathological examination with immunohistochemistry and T-cell receptor gamma (TRG) molecular clonality testing, the latter proving essential for differentiating malignant lymphocyte proliferation from benign inflammatory conditions that can mimic lymphoma microscopically. Confirmation through positive TRG clonality testing established definitive diagnosis when morphological findings alone remained ambiguous, highlighting the diagnostic value of this molecular technique in equine species and their relatives. For practitioners managing cutaneous neoplasia in donkeys, this case underscores that whilst mycosis fungoides remains uncommon, it warrants inclusion in differential diagnoses for chronic, progressive skin lesions unresponsive to standard therapies, and that access to immunophenotyping and clonality testing can transform diagnostic certainty in diagnostically challenging cases. Recognition across donkey populations is particularly relevant given the species' frequent presentation for dermatological complaints, and practitioners should maintain vigilance for unusual cutaneous lymphoproliferative conditions that might otherwise be misclassified as benign dermatitis or infection.
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Practical Takeaways
- •Cutaneous epitheliotropic T-cell lymphoma should be considered in the differential diagnosis of persistent or progressive skin lesions in donkeys, not just horses and other species
- •TRG clonality testing is a valuable diagnostic tool when histology and immunophenotyping are ambiguous, helping confirm malignant versus benign lymphocyte proliferation
- •A multidisciplinary diagnostic approach combining clinical assessment, histopathology, immunohistochemistry, and molecular testing provides the most reliable diagnosis of this condition
Key Findings
- •First reported case of cutaneous epitheliotropic T-cell lymphoma (mycosis fungoides) in a donkey
- •Diagnosis confirmed through combination of clinical presentation, histological findings, immunohistochemical analysis, and positive T-cell receptor gamma clonality test
- •Standard diagnostic approach using morphological, immunophenotypic, and molecular clonality testing successfully differentiated malignant from benign lymphocyte proliferation