Basaloid Trichoblastoma in a ۵-year-old male Alaskan Malamute dog: Histopathological and Case Study

Background: Trichoblastoma is a rare, benign, slow-growing cutaneous neoplasm that arises from the germinal layer of the hair follicle. These lesions are often pigmented. In dogs, Trichoblastomas usually appear as solitary, dome-shaped, alopecia-like nodules that may also develop into ulcers. Treatment of Trichoblastoma in dogs is usually successful through surgical excision. In this study, a case of basaloid Trichoblastoma is reported in a ۵-year-old male Malamute who was referred to a veterinary hospital due to the presence of a dark nodular mass in the left pinna. Methods: On clinical examination, the mass was approximately ۰.۵ cm in diameter and its surface showed ulcerative changes. The mass was completely removed and submitted to the diagnostic pathology. Histopathologic evaluation revealed dermal mass composed of islands of basaloid cells located in the deep dermis. These cell islands were surrounded by a fibroblastic stroma. Mitosis was rare. In immunohistochemical evaluation using CD۱۰ and CD۳۴ markers, the peritumor stroma showed a strongly positive reaction, while the tumor cells had weak staining. Based on the histopathological and immunohistochemical findings, the lesion was diagnosed as Basaloid Trichoblastoma. Results and conclusion: This report aims to provide a precise description of histopathological features of Basaloid Trichoblastoma. The main differential diagnoses of Basaloid richoblastoma in dogs are BCC and Melanoma. The purpose of using IHC markers CD۱۰ and CD۳۴ is to accurately distinguish Trichoblastoma from BCC. In Basaloid Trichoblastoma, CD۳۴ is positive in the peritumoral stroma, while CD۱۰ is negative in the tumor cells. Although more specific marker such as Melan-A is recommended to definitively exclude melanoma. According to the diagnosis, the treatment strategies would differ significantly. Basaloid Trichoblastoma is a benign follicular lesion that can be surgically removed with a narrow margin of surrounding tissue. The diagnosis of this lesion is based on histological criteria combined with immunohistochemical staining.

کلیدواژه ها:

Malamute Dog ، Basaloid Trichoblastoma ، Cutaneous ، Histopathology