TRICHOBLASTOMA WITH ATYPIA AND FIBROMYXOID PROLIFERATION IN A DOG

Karla Geovanna Pereira Nascimento; Raquel Rangel Teles Nunes Valcacio; Paula Dias Retamero; Adriano De Sales Araujo; Reina Isabel Argueta Cartagena; Stanley Nobre lima; Edgar da Costa Albuquerque; Asheley Henrique Barbosa Pereira; Vivian de Assunção Nogueira Carvalho; Ticiana do Nascimento França

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Trabalho

Título do Trabalho

TRICHOBLASTOMA WITH ATYPIA AND FIBROMYXOID PROLIFERATION IN A DOG

Autores

Karla Geovanna Pereira Nascimento
Raquel Rangel Teles Nunes Valcacio
Paula Dias Retamero
Adriano De Sales Araujo
Reina Isabel Argueta Cartagena
Stanley Nobre lima
Edgar da Costa Albuquerque
Asheley Henrique Barbosa Pereira
Vivian de Assunção Nogueira Carvalho
Ticiana do Nascimento França

Modalidade

Resumo Simples

Área temática

Outras áreas temáticas

Data de Publicação

22/05/2026

País da Publicação

Brasil

Idioma da Publicação

pt-BR

Página do Trabalho

https://www.even3.com.br/anais/x-simposio-internacional-ciencias-veterinarias/1434529-trichoblastoma-with-atypia-and-fibromyxoid-proliferation-in-a-dog

ISBN

978-65-272-2456-3

Palavras-Chave

canine, diagnosis, dermatopatology, histology, neoplasia

Resumo

Trichoblastoma is a common benign hair follicle tumor, typically affecting older animals. However, the early-life occurrence is exceptionally rare and poorly documented in veterinary literature. Furthermore, the presence of marked fibromyxoid tissue can complicate the histopathological diagnosis. This study describes a case of trichoblastoma with atypia and marked fibromyxoid tissue in a young dog. A 2-year-old female Shih Tzu was presented to the Veterinary Hospital of the Federal Rural University of Rio de Janeiro (UFRRJ) with a history of a cutaneous mass located in the left cranial parietal region since birth, which had progressively increased in size. The mass was surgically excised with wide margins. The animal showed post-surgical stability, not requiring oncological treatment through chemotherapy sessions. Tissue samples were fixed in 10% neutral-buffered formalin and submitted for histopathological examination. Grossly, the mass consisted of two distinct portions. One component was pedunculated, irregular, firm, and white, measuring 5 × 4 × 3 cm, with an ulcerated surface. At its base, there was a second nodular portion measuring 3 × 4 × 4 cm, which was soft and white on the cut surface. Microscopically, expanding the dermis, replacing adnexal structures, is a multilobular, unencapsulated, and infiltrative, moderately cellular neoplastic proliferation composed of well-differentiated basaloid-cuboidal cells arranged in nests and cords, partially forming a ribbon-like pattern, supported by a dense fibrocallagenous stroma. Neoplastic cells had scant cytoplasm and ovoid basophilic nuclei. Anisocytosis, anisokaryosis, and pleomorphism were mild throughout most of the lesion, although one area showed moderate pleomorphism and atypia. Three mitotic figures, both typical and atypical, were identified per 10 high-power fields (40× objective, FN22/2.37 mm²). Stellate spindle cells resembling fibroblasts, embedded in a myxoid matrix, were noticed interspersed among the neoplastic cells. These cells exhibited moderate eosinophilic to slightly basophilic cytoplasm and ovoid basophilic nuclei, sometimes arranged around blood vessels. Scattered lymphoid follicles were also observed. Based on the microscopic findings, the diagnosis was trichoblastoma with a focus of atypia, and the base of the lesion exhibited a fibromyxoid proliferation. Trichoblastomas present a low risk of recurrence, with surgical excision being the indicated treatment. To the clinician’s knowledge, the patient has not developed recurrence or other postoperative complications to date. This case shows that basaloid tumors should be considered in the differential diagnosis of cutaneous neoplastic proliferations in dogs, and it also highlights that the associated fibromyxoid reaction may represent a prominent stromal response induced by the epithelial neoplastic cells. Although trichoblastomas are benign neoplasms with behavior not typically associated with metastasis, little is known about the biological significance of the fibromyxoid proliferative component. The findings reinforce the importance of complete histologic evaluation to properly characterize these lesions and support appropriate clinical decisions.

Título do Evento: X Simpósio Internacional em Ciências Veterinárias | X International Symposium in Veterinary Sciences
Cidade do Evento: Seropédica
Título dos Anais do Evento: Anais do X Simpósio Internacional em Ciências Veterinárias (X SINCVET)
Nome da Editora: Even3
Meio de Divulgação: Meio Digital

Como citar

NASCIMENTO, Karla Geovanna Pereira et al.. TRICHOBLASTOMA WITH ATYPIA AND FIBROMYXOID PROLIFERATION IN A DOG.. In: Anais do X Simpósio Internacional em Ciências Veterinárias (X SINCVET). Anais...Seropédica(RJ) UFRRJ, 2025. Disponível em: https//www.even3.com.br/anais/x-simposio-internacional-ciencias-veterinarias/1434529-TRICHOBLASTOMA-WITH-ATYPIA-AND-FIBROMYXOID-PROLIFERATION-IN-A-DOG. Acesso em: 09/11/2026