Hair Follicle Tumors in Dogs: A Report of Two Cases

The document reported two cases of hair follicle tumors in dogs, specifically trichoblastoma and trichoepithelioma. In the first case, a 10-year-old mixed breed dog had a trichoblastoma, characterized by polygonal basaloid cells in nests and islands, separated by collagenous stroma. The second case involved an 8-year-old mixed breed male dog with trichoepithelioma, featuring multiple keratin-filled cysts lined by basaloid cells. Both tumors were benign and demonstrated the complex histology typical of hair follicle tumors, which mimic normal hair structures. The study highlighted the variability in histopathologic appearance due to the complex nature of hair follicle differentiation.