Peer-reviewed veterinary case report
Cat limping with a granular tumor on her toe explained
By Cruz Otero, José D et al.·Published in Veterinary clinical pathology·2023·Department of Population Medicine and Diagnostic Sciences, United States·View original on PubMed →
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Original publication title: Granular variant of a histiocytic tumor on the toe of a cat: Case report and literature review.
- Species:
- cat
Plain-English summary
A 16-year-old female domestic shorthaired cat was brought to the vet because she was limping and had a noticeable mass on her toe. After examining the mass, the vet found it was a type of tumor made up of unusual cells with granules inside them. The tumor was removed surgically, and further tests confirmed it was a new variant of a histiocytic tumor, which is a type of growth that can occur in cats. The cat's condition after surgery wasn't detailed, but typically, removal of such tumors can lead to improvement in symptoms.
People also search for: cat toe mass · cat limping · histiocytic tumor in cats · cat tumor removal · cat foot problems
Abstract
A 16-year-old female spayed domestic shorthaired cat was examined for lameness and a mass on the fourth digit of the right hindlimb. Cytologic examination of an aspirate of the mass revealed large discrete cells admixed with low numbers of well-granulated mast cells. The discrete cells contained single to many variably sized light pink to purple granules in their cytoplasm and had pleomorphic nuclei, with intranuclear cytoplasmic inclusions. Karyomegalic, binucleated and multinucleated cells were seen. Histologic examination of formalin-fixed sections of the excised mass showed a mildly infiltrative, unencapsulated, multinodular dermal mass that extended into the subcutis and consisted of similar discrete cells. On immunohistochemical staining, the tumor cells expressed ionized calcium-binding adapter molecule 1 (Iba1) and CD18. The tumor cells did not express CD3, CD20, CD117, pancytokeratin (AE1/AE3), melanoma antigen (Melan-A), multiple myeloma oncogene-1 (MUM1), melanoma-associated antigen (PNL-2), and S-100. Low numbers of tumor cells expressed CD204 and protein gene product 9.5 (PGP9.5). Granules were variably positive for Periodic-acid Schiff (PAS) and Alcian blue. On transmission electron microscopy, the cells contained filopodia, abundant endoplasmic reticulum, and moderate numbers of low-density membrane-bound granules. This case documents a previously undescribed granular variant of a histiocytic tumor in a cat.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/35751153/