The Importance of Ultrasonography in the Evaluation of Mammary Tumors in Bitches

Simple Summary: Mammary tumors are one of the most common neoplasms in bitches and represent an important concern in small animal practice. Clinical staging requires an extensive clinical evaluation and definitive diagnosis is obtained by means of histopathological evaluation. Ultrasonography is a well-established imaging technique in veterinary medicine that allows detailed evaluation of the genital system. Other advanced sonographic techniques, such as Doppler, elastography and contrast-enhanced ultrasound (CEUS) have raised interest in the scientific community and researchers have been performing studies to evaluate whether these techniques can accurately differentiate tumoral lesions. This paper reviews current information regarding the sonographic findings of mammary tumors in each different ultrasound technique. Overall, based on the information present to this date, elastography is the most reliable ultrasound technique to distinguish benign lesions from malignant tumors. Nevertheless, each technique demonstrates important findings that could guide the therapeutic approach and can be applied in veterinary practice. Additionally, further studies are required to evaluate the potential of each technique to monitor therapeutic progression. The high incidence of mammary tumors in small animals is concerning. Patient history, clinical examination, physical evaluation, and imaging studies are important for clinical staging. Ultrasonography is commonly applied to investigate the presence of abdominal metastasis. However, it has been shown to provide important information regarding mammary tumors' architecture and advanced sonographic techniques can provide information regarding neovascularization, stiffness, and perfusion. Different techniques have been investigated to determine accuracy to predict the lesions' histological classification. This paper reviews the information regarding each sonographic technique in the evaluation of mammary tumors, describing the most common findings and their potential to accurately assess and predict malignancy. Even though the gold standard for the diagnosis of mammary lesions is the histopathological examination, some ultrasonographic features described can predict the potential of a lesion being malignant. Among the different sonographic techniques, elastography can be considered the most reliable modality to accurately differentiate benign from malignant tumors when malignant lesions present increased stiffness. However, the combination of all sonographic techniques can provide important information that can lead to a better therapeutic approach and clinical staging. Furthermore, the potential of the sonographic study, especially CEUS to monitor therapeutic progression, demonstrate the need of further studies.