Invasive lobular carcinoma
Invasive lobular carcinoma is breast cancer arising from the lobules of the mammary glands. It accounts for 5–10% of invasive breast cancer. Rare cases of this carcinoma have been diagnosed in men.
Types
The histologic patterns include:| Type | Prevalence | Description | Image |
| Classical | 40% | Round or ovoid cells with little cytoplasm in a single-file infiltrating pattern, sometimes concentrically giving a targetoid pattern | |
| Mixed | 40% | No dominant pattern | - |
| Solid | 10% | Sheets of classical-appearing cells with little intervening stroma | - |
| Alveolar | 5% | Aggregates of classical-appearing cells | - |
| Tubulolobular | 5% | Cells form microtubules in >90% of tumor | - |
| Pleomorphic | Classical-appearing but with pleomorphic cells. It may include signet-ring cells, or plasmacytoid cells which have abundant cytoplasm and eccentric nuclei. |
Prognosis
Overall, the five-year survival rate of invasive lobular carcinoma was approximately 85% in 2003.Diagnosis
On mammography, ILC shows spiculated mass with ill-defined margins that has similar or lower density than surrounding breast tissues. This happens only at 44–65% of the time. Architectural distortion on surrounding breast tissues is only seen in 10–34% of the cases. It can be reported as benign in 8–16% of the mammography cases.Ultrasound has 68–98% sensitivity of detecting ILC. ILC shows irregular or angular mass with hypoechoic or heterogenous internal echoes, ill-defined or spiculated margins, and posterior acoustic shadowing.
Loss of E-cadherin is common in lobular carcinoma but is also seen in other breast cancers.