Invasive lobular carcinoma (ILC) is breast cancer arising from the lobules of the mammary glands.

[2][3] Rare cases of this carcinoma have been diagnosed in men (see male breast cancer).

[4] The histologic patterns include:[6][7][8] Overall, the five-year survival rate of invasive lobular carcinoma was approximately 85% in 2003.

[9] On mammography, ILC shows spiculated mass with ill-defined margins that has similar or lower density than surrounding breast tissues.

ILC shows irregular or angular mass with hypoechoic or heterogenous internal echoes, ill-defined or spiculated margins, and posterior acoustic shadowing.