Hypercalcemia in bitches with malignant mammary neoplasms

Abstract

Malignant hypercalcemia is a paraneoplastic syndrome. It has been detected in several types of malignant tumours in dogs, such as lymphomas, and also in mammary neoplasms, without the exact determination of the mechanisms involved in its occurrence as well as its incidence. In this study, 100 bitches with mammary malignant neoplasia, diagnosed by histopathological analysis, were submitted to clinical evaluation for disease staging, haematological evaluation, serum biochemistry, including renal function tests, hepatic and total calcium serum levels and ionized fraction. These parameters were analyzed at the time of the initial attendance and 30 days after the treatment. The most frequent histological pattern was carcinoma in mixed tumors (26%). In 52% of the diseased dogs, hypercalcemia was observed by means of ionized calcium dosing, which was not verified by means of total calcium dosing, where only 4% presented hypercalcemia. No correlation was found between hypercalcemia and the histological pattern of the neoplasms. However, the correlation was verified between hypercalcemia and more advanced stages of the disease, mainly from stage III, suggesting that the detection of hypercalcemia may be correlated with worse prognosis, showing the importance of the research concerning the presence of paraneoplastic syndromes in bitches with mammary neoplasms.