Malignant Follicular Tumors With Myxoid Mucopolysaccharide-Like Stroma on Cytology and Histology in a Cat.

This case highlights the cytologic and histologic complexity of diagnosing malignant follicular tumors in cats. The presence of abundant myxoid-like mucin-rich stroma may be associated with aggressive biological behavior. Malignant trichoepithelioma should remain a differential diagnosis for basaloid epithelial neoplasms in cats, even in the absence of cytologic evidence of keratinization. This report adds to the limited literature on feline malignant follicular tumors and emphasizes the need for further investigation into their diagnostic criteria and biological behavior.