Carcinoma de células fusiformes em equino

Abstract

Spindle cell carcinoma (SpCC) is an uncommon neoplasm in humans and extremely rare in animals, originating from a variation of squamous cell carcinoma (SCC) that affects cells of epithelial origin, leading to the appearance of variable cytomorphological changes. Based on clinical assessments and complementary tests, the aim is to describe a case of SpCC developed in the nasal cavity of a mixed-breed horse aged approximately 10 years, with a brown coat and weighing 360 kg, treated at the Veterinary Hospital of the Federal University of Paraíba. Clinically, the patient presented symptoms of sinusitis associated with the size of the tumor, which obstructed the passage of air through the right nostril. Hematologically, the variables were within the reference limits for the species. Radiographs showed increased soft tissue radiopacity in the right nasal cavity. Endoscopic examinations showed adhesions and local infiltration of the tumor. The patient underwent surgical procedures for tumor excision, trepanation of the maxillary and frontal sinuses, as well as ostectomy of the nasal bone. Histopathology revealed a proliferation of spindle-shaped, stellate and rounded cells, associated with a slightly eosinophilic material compatible with extracellular myxoid matrix. Immunohistochemical analysis showed positive staining for vimentin and cytokeratin pan clone AE1/AE3. The combination of the results obtained was essential for the diagnosis of SpCC, making this the first case described in an equine. Even though SpCC has a high metastatic potential, no signs of metastasis were observed in this patient and despite the degree of local infiltration, total excision was possible, which, combined with pharmacological protocols, resulted in a cure for the patient, who has so far had no signs of recurrence.