Intramammary metastases: comparison of mammographic and ultrasound features

To describe the mammographical and ultrasound features of IM, and to compare radiological patterns of IM arising from different malignancies.

A retrospective search in the statistical database of our institution from January 2000 to December 2009 revealed 51 cases of intramammary metastases from solid malignancies. Additionally, a retrospective search in the Pubmed database was performed. Publications in the time interval from 1980 to 2010 were considered. After thorough analysis, 119 articles with 229 patients were involved in the study. Therefore, together with our cases our analysis comprises 280 patients. Mammographic and ultrasound findings of different IM were analyzed.

The detected metastases showed two main radiological patterns: intramammary masses (81.5%) and architectural distortion (18.5%). Carcinomas of the stomach caused more frequently an architectural distortion, whereas other malignancies tended to present as intramammary masses. The size of the masses ranged from 2 to 104 mm. The largest lesions occurred in rhabdomyosarcoma, followed by hepatocellular carcinoma and squamous cell carcinomas of the head and neck region. The smallest lesions arose from malignancies of the thyroid gland carcinoma. Most IM showed circumscribed margins, while breast lesions in rhabdomyosarcoma were rather microlobulated. On ultrasound, IM from lung cancer were usually inhomogenously hypoechoic with circumscribed margins and showed posterior shadowing in almost 50% of the cases. Breast metastases from ovarian carcinoma had typically microlobulated margins and posterior enhancement.

IM can present with a broad spectrum of radiological features. Their imaging findings vary depending on the primary tumor.