What is a defining characteristic of invasive lobular carcinoma?

Invasive lobular carcinoma is known for its tendency to present as multiple lesions rather than as a single, distinct mass. This characteristic is due to the unique growth pattern of lobular carcinoma, where the cancer cells invade the surrounding breast tissue in a subtle and diffuse manner. As a result, it can often be found in multiple areas of the breast, even if the patient has a history of only a single breast cancer lesion. This pattern contrasts with other forms of breast cancer that typically manifest as a singular, more defined tumor.

Additionally, this can make the detection of invasive lobular carcinoma more challenging, as it may not always present as a palpable lump, which is why a patient may have a history of breast cancer along with multiple lesions. The recognition of this growth behavior is crucial for proper diagnosis and treatment planning.