Invasive lobular carcinoma is a type of breast cancer that begins in the lobules, which are the glands that produce milk. It is characterized by small, non-cohesive cells that invade surrounding breast tissue. This cancer often grows in a subtle, diffuse pattern, making it harder to detect in mammograms compared to other types of breast cancer. This form of carcinoma can be more challenging to diagnose early due to its unique growth pattern. Symptoms may include a thickening or change in the breast tissue, but it may not always form a distinct lump. Early detection and treatment are crucial for better outcomes.