**Core Concept**
Infiltrating lobular carcinoma (ILC) is a subtype of breast cancer characterized by the invasion of cancer cells into the lobules of the breast tissue. This type of cancer is often associated with a high nuclear grade and a tendency to be multifocal.

**Why the Correct Answer is Right**
ILC tends to grow along the ducts and lobules, making it difficult to detect and often leading to a delayed diagnosis. The cancer cells in ILC are typically small and uniform, with a high nuclear grade, which can make them appear as "single-file" cells along the ducts. This unique growth pattern is a key feature of ILC and can help differentiate it from other types of breast cancer.

**Why Each Wrong Option is Incorrect**
**Option A:** ILC is often associated with a high nuclear grade, but this statement is incomplete and does not capture the unique growth pattern of ILC.
**Option B:** While ILC can be multifocal, this statement does not address the specific characteristics of ILC that distinguish it from other breast cancer subtypes.
**Option C:** ILC is not typically associated with a high mitotic rate, which is a characteristic of some other breast cancer subtypes.

**Clinical Pearl / High-Yield Fact**
ILC is often referred to as "ductal carcinoma in situ with invasion" because the cancer cells can grow along the ducts and lobules, making it difficult to distinguish from ductal carcinoma in situ (DCIS).

**Correct Answer: C**