Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which of the following is NOT a common primary site for metastatic-type cancer to spread to the orbit?

1. Breast

2. Lung

3. Kidney

4. Skin (melanoma)

The correct answer is: Kidney

Metastatic spread to the orbit, the area surrounding the eye, can occur from various primary cancer sites, with some being more common than others. The kidneys are less frequently associated with orbital metastases compared to breast, lung, and skin (melanoma) cancers, which are well-documented sources of such spread. Breast cancer is a well-known cause of orbital metastases, as breast malignancies can lead to a variety of complications and spread beyond the initial site. Lung cancer is another major contributor, given the proximity of the lungs to the thoracic cavity and its overall high incidence. Skin cancer, particularly melanoma, is notorious for metastasizing to distant sites, including the orbit, due to its aggressive nature. In contrast, while kidney cancer can spread to various regions of the body, it is not commonly associated with metastases to the orbit. The rarity of renal cancer as a source of orbital metastases makes it the least likely answer in this context. Therefore, kidney cancer stands out as the appropriate choice for the option that is not a typical primary site for this type of spread.