Invasive carcinoma of no special type

Formerly Invasive Ductal Carcinoma (IDC). Accounts for 70-80% of all invasive breast cancers.

Radiological features:

• Mammography: Irregular, high-density mass with spiculated margins. Associated pleomorphic calcifications common.
• US: Hypoechoic, irregular mass, anti-parallel orientation (taller-than-wide), posterior acoustic shadowing, echogenic halo (desmoplastic reaction).
• MRI: Rapid initial enhancement with washout (Type 3 curve) or plateau (Type 2 curve). Rim enhancement is a specific sign of malignancy.