Parotid gland adenocarcinoma in a cow: case report

Abstract

ABSTRACT A 9-year-old Girolando dairy cow, weighing 400kg, with a history of increased volume in the right parotid region, which extended to the submandibular region, was assisted. Fine needle aspiration cytology was performed, and the cytological findings were consistent with malignant neoplasm of epithelial origin (carcinoma). Because of the unfavorable prognosis, the animal was euthanized and submitted to an anatomopathological examination. Samples of the increased parotid and affected lymph nodes were collected for histopathological evaluation. The microscopic changes were accentuated features of anaplasia, moderate cell proliferation, atypical mitotic figures, and necrosis. Stroma ranged from delicate to scirrhous, and the tumor boundaries were not distinct. These findings substantiated the preliminary histomorphological diagnosis of undifferentiated carcinoma with metastasis in lymph nodes. Immunohistochemical tests were performed with anti-CK Pan (clone AE1AE3), anti-CK HMW (clone 34βE12), anti-CK19 (clone RCK108), anti-vimentin (clone V9), anti-S100 (polyclonal), and anti-androgen (polyclonal) antibodies. The immunophenotype favored the diagnosis of salivary gland adenocarcinoma. Despite the rareness in cattle, salivary gland adenocarcinoma should be considered in the differential diagnosis of diseases that occur with increased volume in the head, lymphadenopathy, drooling, dysphagia, and progressive weight loss.