Breast Carcinoma with Pulmonary Metastasis in Armadillo (Eupharactus sexcinctus)

Abstract

Background: Breast neoplasms are among the most common neoplastic conditions affecting domestic animals and are considered the most common type of cancer affecting women, bitches, and cats. However, there are few reports on breast neoplasms in wild animals, and there is no record of their occurrence in armadillos worldwide. Breast neoplasms are hormone-dependent neoplasms that often cause lymph node and pulmonary metastases. The diagnosis is based on the patient’s history, complete physical examination, and complementary tests. Here we report a case of mammary neoplasia with pulmonary metastasis in an armadillo (Euphractus sexcinctus).Case: A senile female armadillo was referred to us for treatment with a history of hyporexia and nodules in both breasts. Ultrasonographic examination revealed a hypoechogenic nodular lesion with a cross-section of approximately 1.3 × 1.4 cm and well-defined borders. The lesion had a circumscribed aspect in the left mammary gland. In the right mammary gland, there was a heterogeneous lesion with cystic formations and anechoic content. Cytopathological examination of the nodules was performed by fine needle aspiration cytology and revealed the presence of epithelial cells with ovoid and aberrant nuclei, anisocariasis, binucleation, coarse chromatin, and a high nucleus to cytoplasm ratio suggestive of carcinoma. The animal had a lean body score due to hyporexia that had evolved to anorexia and was undergoing supportive treatment. Nevertheless, the animal died two months after the cytologic diagnosis. A necropsy was performed. Cutting of the breast nodules revealed a hardened pale yellow material. The animal had pronounced pleural effusion, hemorrhage, and numerous pale yellow nodules of various sizes with firm consistency throughout the lung parenchyma. It also had hepatomegaly and splenomegaly. Fragments of various organs were fixed in 10% buffered formalin, routinely processed, embedded in paraffin, and stained with hematoxylin and eosin. Upon microscopic examination, the mammary nodes demonstrated a proliferation of epithelial cells organized into tubular structures with intraluminal papillary projections. The cells had a polyhedral profile and a high nucleus to cytoplasm ratio, moderately pleomorphic evident nuclei. Some cells had coarse chromatin. We observed moderate anisocytosis and anisocariasis, as well as mitotic figures. In the lungs, nodules with the same microscopic characteristics of the mammary nodes were observed in addition to intense congestion and multifocal hemorrhages.Discussion: This type of mammary carcinoma is considered an invasive neoplasm of ductal origin, and is morphologically characterized by rounded, ovoid, or angulated tubule formations with intraluminal projections. The patient’s prognosis is directly related to the occurrence of vascular invasion and metastasis. If present, these conditions may lead to reduced patient survival. Since the lungs are the most common sites of metastasis, pleural effusion caused by vessel erosion due to the presence of tumors is common and can in most cases lead to respiratory failure and eventually death. In this case, the association between the necropsy findings and the results of the histopathological examination enabled us to classify the carcinoma as one of mammary origin and of the tubulopapillary type with pulmonary metastasis. This is the first report of mammary carcinoma in an armadillo in captivity in the world.