Melanocitoma-acantoma em um cão
Mazaro, Renata DalcolLorensetti, Douglas MiottoHerbichi, Alana PivotoFighera, Rafael Almeida
Background: Melanocytic neoplasms are skin tumors that often occur in dogs. However, melanocytoma-acanthoma, alsocalled melanoacanthoma, is a benign melanocytic neoplasm rarely reported in this species, which has been described onlythree times in the veterinary literature. Briefly, this tumor is characterized by a single, painless, darkly pigmented and firmcutaneous papule or nodule. Histologically, it is composed of mixed populations of well-differentiated melanocytes andkeratinocytes, unlike traditional melanocytic tumors (melanoma and melanocytoma). These cells are arranged in lobulessurrounded by collagenous stroma. Melanocytes are large epithelioid cells containing varying amounts of melanin. Keratinocytes form anastomosing trabeculae with peripheral palisading, and small cysts containing amorphous or laminatedkeratin. The definitive diagnosis of melanocytoma-acanthoma is based on histopathological findings. This report describesa case of melanocytoma-acanthoma in a dog in Brazil.Case: A 9-year-old female miniature Schnauzer dog was examined at the Veterinary Hospital of the Federal Universityof Santa Maria, where a single, firm, pigmented papule was found in the auricle. The lesion had started 15 days earlier.Hematological tests and serum biochemistry profile were normal. An excisional biopsy of the papule was surgically removed and subjected to histopathological examination. The tissue was fixed in 10% neutral buffered formalin, processedroutinely and embedded in paraffin wax. Sections were stained with hematoxylin and eosin (HE). A histopathologicalexamination revealed a nonencapsulated, well-defined, extensive, densely cellular proliferation located in dermis. Thisproliferation was composed of lobules and nests of well-differentiated stratified squamous epithelium closely associatedwith neoplastic melanocytes, surrounded by thin bundles of fibrous stroma. A diagnosis of...(AU)
Texto completo