Equine skin tumours in 20 horses resembling three variants of human melanocytic naevi.
Abstract: Melanocytic tumours are important in horses, especially grey horses. Intradermal common melanocytic naevi, cellular blue naevi and combined cellular blue naevi are subgroups of human melanocytic tumours, which have not been reported in horses. In this study, we describe 20 horses with skin tumours similar to these naevi of humans. These tumours represented individual skin masses in male and female horses of different breeds. Tumours resembling human intradermal common melanocytic naevi were noted in 12 horses aged between 2 and 17 years. Seven horses aged between 4 and 15 years developed cutaneous lesions similar to human cellular blue naevi. A combined cellular blue naevus-like tumour was diagnosed in a 20-year-old horse. All tumour types formed expansile, well-demarcated, non-encapsulated, symmetrical masses. Tumours similar to intradermal common melanocytic naevi were composed of nests of round and spindeloid neoplastic cells, often embedded in myxomatous stroma. Lesions resembling cellular blue naevi were formed by intradermal bundles of ovoid to elongated cells separated by collagen fibres. The combined cellular blue naevus-like tumour resembled human cellular blue naevus with in addition, an overlying junctional common melanocytic naevus. Neoplastic cells in all groups contained varying amounts of melanin pigment and were immunopositive for S100. These equine skin tumours differ from the commonly recognized equine melanocytic tumours by their cytomorphological features, random location and the absence of an increased tumour frequency in grey horses. The resemblance of these tumours to three distinct subgroups of human naevi expands the complexity of equine proliferative cutaneous melanocytic lesions.
Publication Date: 2009-04-03 PubMed ID: 19374725DOI: 10.1111/j.1365-3164.2009.00741.xGoogle Scholar: Lookup
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- Journal Article
Summary
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This study examines a type of skin tumor found in horses that resembles melanocytic naevi, a type of mole that can form on human skin. The research found that these horse tumors share characteristics with three different subgroups of melanocytic tumors found in humans – intradermal common melanocytic naevi, cellular blue naevi and combined cellular blue naevi.
Types of Melanocytic Tumours
- The research team identified horses with tumors similar to three subtypes of human melanocytic tumors: intradermal common melanocytic naevi, cellular blue naevi, and combined cellular blue naevi. These categories have not been previously reported in horses.
- Twelve of the cases in the study resembled human intradermal common melanocytic naevi. The affected horses ranged in age from 2 to 17 years.
- Seven of the cases resembled human cellular blue naevi, with affected horses ranging from 4 to 15 years old.
- One case of a combined cellular blue naevus-like tumor was discovered in a 20-year-old horse.
Characteristics of the Tumours
- All types of tumors found were well defined, non-encapsulated, symmetrical masses, which differed from the typical equine melanocytic tumors.
- Tumors similar to intradermal common melanocytic naevi were found to be composed of nests of round and spindle-shaped neoplastic cells within a myxomatous stroma.
- Tumors similar to cellular blue naevi were formed by intradermal bundles of elongated cells separated by collagen fibers.
- The combined cellular blue naevus-like tumor resembled human cellular blue naevi, but with an added overlying junctional common melanocytic naevus.
- All types of tumors contained varying amounts of melanin pigment and were immunopositive for S100, a protein often used as a marker for certain types of tumors.
Further Insights and Implications
- These horse skin tumors differ from the regularly recognized equine melanocytic tumors in their structure, random location, and the fact that they aren’t more common in grey horses (unlike typical melanocytic tumors).
- The similarity of these tumors to human naevi suggests a more complex landscape of equine proliferative cutaneous melanocytic lesions.
- The finding may also have implications for the study of similar tumours in humans, providing further avenues for research.
Cite This Article
APA
Schöniger S, Summers BA.
(2009).
Equine skin tumours in 20 horses resembling three variants of human melanocytic naevi.
Vet Dermatol, 20(3), 165-173.
https://doi.org/10.1111/j.1365-3164.2009.00741.x Publication
Researcher Affiliations
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Herts, UK. sschoeniger@rvc.ac.uk
MeSH Terms
- Animals
- Diagnosis, Differential
- Female
- Horse Diseases / classification
- Horse Diseases / pathology
- Horses
- Immunohistochemistry / veterinary
- Male
- Melanocytes / pathology
- Melanoma / pathology
- Nevus, Blue / classification
- Nevus, Blue / pathology
- Nevus, Blue / veterinary
- Nevus, Pigmented / classification
- Nevus, Pigmented / pathology
- Nevus, Pigmented / veterinary
- Skin Neoplasms / classification
- Skin Neoplasms / pathology
- Skin Neoplasms / veterinary
Citations
This article has been cited 5 times.- Pimenta J, Prada J, Cotovio M. Equine Melanocytic Tumors: A Narrative Review. Animals (Basel) 2023 Jan 10;13(2).
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- van der Weyden L, Brenn T, Patton EE, Wood GA, Adams DJ. Spontaneously occurring melanoma in animals and their relevance to human melanoma. J Pathol 2020 Sep;252(1):4-21.
- van der Weyden L, Patton EE, Wood GA, Foote AK, Brenn T, Arends MJ, Adams DJ. Cross-species models of human melanoma. J Pathol 2016 Jan;238(2):152-65.
- Bulnes F, Argüelles D, Buzón A, García-Álamo K, Rodríguez-Gómez IM, Hernández E, Mozos E. Concomitant melanoma and keratoma affecting the equine digit: clinical, pathological, and long-term follow-up findings. BMC Vet Res 2024 Oct 1;20(1):444.
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