Lymphoid tissue is seen in which parotid tumor

**Core Concept**
Lymphoid tissue in parotid tumors is associated with autoimmune or inflammatory conditions, or specific types of neoplasms. This phenomenon is linked to the aberrant immune response and the interaction between tumor cells and the immune system.

**Why the Correct Answer is Right**
Warthin's tumor, also known as adenolymphoma, is a benign neoplasm of the parotid gland characterized by the presence of lymphoid tissue. The tumor consists of lymphoid follicles surrounded by oncocytes, which are epithelial cells with abundant cytoplasm. The lymphoid tissue in Warthin's tumor is thought to be a result of the interaction between the oncocytes and the immune system, leading to the activation of lymphoid cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the presence of lymphoid tissue in parotid tumors.
**Option B:** Pleomorphic adenoma, also known as benign mixed tumor, is the most common type of parotid tumor, but it does not typically contain lymphoid tissue.
**Option C:** This option is not a specific type of parotid tumor associated with lymphoid tissue.

**Clinical Pearl / High-Yield Fact**
Warthin's tumor is a benign neoplasm that can be distinguished from malignant parotid tumors by the presence of lymphoid tissue. It is also characterized by a strong association with smoking and a higher incidence in males.

**Correct Answer:** C. Warthin's tumor.