Peer-reviewed veterinary case report
Multicentric mast cell tumors in a horse.
- Journal:
- Veterinary clinical pathology
- Year:
- 2010
- Authors:
- Millward, Laurie M et al.
- Affiliation:
- Department of Veterinary Biosciences · United States
- Species:
- horse
Plain-English summary
A 6-year-old female Rocky Mountain horse was brought in because she had swelling and draining sores on her left front and left hind legs for two weeks. Tests on the fluid from these areas showed a lot of certain white blood cells called eosinophils and unusual-looking mast cells, leading to a diagnosis of mast cell tumor (a type of cancer). Further examination of tissue samples confirmed this diagnosis and showed that the mast cells were expressing a specific marker called CD117, which helps distinguish this type of tumor from other similar conditions. This case is notable because it is the first time a horse has been reported with mast cell tumors presenting in this way. The treatment approach and outcome were not detailed, but the findings highlight the importance of specific staining techniques in diagnosing these tumors in horses.
Abstract
A 6-year-old female Rocky Mountain horse was presented for evaluation of draining tracts and distal limb subcutaneous edema on the left front and left hind limbs that had been present for 2 weeks. Direct smears of fluid collected by fine-needle aspiration of subcutaneous fluid from both limbs were highly cellular with a predominance of eosinophils accompanied by numerous, moderately atypical, variably granulated mast cells. The cytologic diagnosis was mast cell tumor (MCT) with prominent eosinophilic infiltration with a differential diagnosis of eosinophilic granuloma. Histologic evaluation of surgical biopsies of lesions from both limbs was performed on sections stained with H&E, toluidine blue, and Luna stains. The histologic diagnosis was MCT, and staining with toluidine blue and Luna stains confirmed the presence of mast cells and eosinophils, respectively. In addition, the mast cells strongly expressed CD117. This is the first reported case of cutaneous mast cell neoplasia in a horse in which primary presenting complaints were draining tracts and distal limb subcutaneous edema involving multiple limbs. This case illustrates the utility of staining for CD117 expression in combination with traditional stains, such as toluidine blue and Luna, in differentiating MCTs from other eosinophilic lesions in horses.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/20412546/