Morphologic Mimics of Invasive Lobular Carcinoma.

Invasive lobular carcinoma of the breast is a relatively common diagnosis. However, other carcinomatous as well as noncarcinomatous neoplasms, either primary or metastatic to the breast, may mimic invasive lobular carcinoma. As treatment may differ, establishing the correct diagnosis is paramount to providing the appropriate care for these patients. This review outlines important mimics of invasive lobular carcinoma and the key clinicopathologic and immunohistochemical features as well as additional studies helpful in establishing their diagnoses.