**Question:** Which of the following is not true about the pleomorphic adenoma of parotid gland?

A. Pleomorphic adenoma is a benign tumor that occurs due to the uncontrolled growth of both epithelial and mesenchymal cells of the salivary gland.
B. Pleomorphic adenoma is the most common type of parotid gland tumor.
C. Pleomorphic adenoma typically presents as a slow-growing, painless mass in the parotid gland region.
D. Pleomorphic adenoma is always associated with a high risk of recurrence after surgical removal.

**Correct Answer: D. Pleomorphic adenoma is always associated with a high risk of recurrence after surgical removal.**

**Core Concept:** Pleomorphic adenoma is a benign tumor originating from the epithelial and mesenchymal cells of the salivary gland. It is a well-differentiated tumor composed of both epithelial and mesenchymal components, making up 5-10% of all salivary gland tumors and 90% of benign parotid gland tumors.

**Why the Correct Answer is Right:** Pleomorphic adenoma is a benign tumor, meaning it is non-cancerous and does not have the potential to spread to other parts of the body. However, the high risk of recurrence after surgical removal is due to the nature of the tumor itself and its complex structure. The tumor is composed of both epithelial and mesenchymal elements, which can lead to residual tumor cells or microscopic tumor spread during surgery. This results in an increased likelihood of the tumor recurring in the same location or nearby.

**Why Each Wrong Option is Incorrect:**

A. Pleomorphic adenoma is a true tumor derived from the uncontrolled growth of both epithelial and mesenchymal cells of the salivary gland. This option is correct, as it describes the origin and nature of pleomorphic adenoma.

B. Pleomorphic adenoma is the most common type of salivary gland tumor. Although pleomorphic adenoma is a common benign tumor, it is not the most common type of salivary gland tumor overall. Mucoepidermoid carcinoma is the most common malignant tumor, while Warthin's tumor is the most common benign tumor of the salivary gland.

C. Pleomorphic adenoma presents as a rapidly growing, painful tumor. Pleomorphic adenoma typically presents as a slow-growing, painless mass in the parotid gland region. This option is correct as it describes the typical presentation of pleomorphic adenoma.

D. Pleomorphic adenoma does not recur after complete surgical excision. As mentioned earlier, pleomorphic adenoma can recur due to the complex nature of the tumor and the presence of both epithelial and mesenchymal elements. This option is incorrect, as pleomorphic adenoma does have a high risk of recurrence despite complete surgical excision due to the tumor's complex structure.

**Clinical Pearl:** When dealing with pleomorphic adenoma, it is essential to ensure complete excision of the tumor to minimize the risk of recurrence. In case of incomplete excision, the patient may require further surgery, radiation therapy, or both to control the tumor. In some cases, the tumor may recur even after complete excision, as seen in option