Sonographic evaluation of infiltrating lobular carcinoma.

Infiltrating lobular carcinoma (ILC), which accounts for 7-10% of all breast malignancies, often poses diagnostic difficulties. The purpose of our study was to correlate the clinical, mammographic, and sonographic findings in each histologic subtype of ILC and to evaluate the sensitivity of sonography in its diagnosis.We reviewed 208 cases of invasive lobular carcinoma. In 81 of these tumors, sonography was performed to further examine a mammographically invisible palpable abnormality or a mammographically subtle lesion. A dedicated breast pathologist classified each of these tumors as pure invasive lobular carcinoma or mixed invasive lobular and ductal carcinoma. Pure ILC tumors were further subclassified as one of five histologic subtypes. We retrospectively studied the clinical, mammographic, and sonographic findings in each histologic tumor subtype.The most common sonographic appearance of ILC was a heterogeneous, hypoechoic mass with angular or ill-defined margins and posterior acoustic shadowing, wh...