**Question:** Most common metastatic tumor in orbit in adult male is due to

A. Prostate cancer
B. Lung cancer
C. Breast cancer
D. Renal cancer

**Core Concept:**
The orbit is a bony cavity in the skull that houses the eye and its surrounding structures. It is a rare location for primary tumors, with most cases being secondary spreads from distant primary sites. Common primary sites for orbital tumors are the prostate, lungs, breast, and kidneys.

**Why the Correct Answer is Right:**
Prostate cancer is the most common primary tumor in adult males, with approximately 10% of cases involving the orbit. Prostate cancer cells can spread to the orbit via the bloodstream, causing symptoms such as proptosis, diplopia, and visual disturbances.

**Why Each Wrong Option is Incorrect:**
B. Lung cancer is the most common primary tumor in adults, but it rarely involves the orbit due to the absence of direct pathway to the orbit. Instead, lung cancer spreads to the orbit via the bloodstream or lymphatic system.
C. Breast cancer is more common in females due to the presence of female sex hormones. Although breast cancer can spread to the orbit, it is less common than prostate cancer.
D. Renal cancer is less common than prostate, lung, and breast cancer as primary tumors in adults. It also rarely spreads to the orbit, making it the least likely choice.

**Clinical Pearl:**
In cases of orbital tumors in adult males, a thorough history and physical examination should be performed to identify the primary site. The presence of risk factors like age, gender, and tumor characteristics can lead to the correct diagnosis and appropriate management.

**Correct Answer:** A. Prostate cancer