Multiple Follicular Abnormalities in a 1-Year-Old Cat Consistent with Basaloid Follicular Hamartomas

The document is a case report describing clinical and histopathological findings in a one-year-old neutered domestic short hair cat, which showed multiple follicular abnormalities consistent with cutaneous diffuse basaloid follicular hamartomas. The cat exhibited clinical signs of diffuse symmetrical alopecia with exaggerated skin markings and intense follicular-centred thickening. Microscopic examination revealed multiple proliferative follicular abnormalities, with the follicles filled with variably pigmented keratin and the epithelial walls of the follicles having multiple small hyperplastic basaloid cells foci. The interfollicular epidermis was also abnormal with multiple small proliferating trichoblastic foci originating from the basal layer. RNAscope testing for feline papillomavirus was negative. This case report provides the first evidence of such findings in a cat.