What is a sebaceous cyst most accurately called?

• A. A cyst
• B. A tumor
• C. A mole
• D. A boil

Answer: (A)

Sebaceous cysts are closed sacs beneath the skin that fill with thick, keratin-rich material. Because it is a sac or pouch, the most accurate label is a cyst. A tumor would be a solid growth of tissue, which a sebaceous cyst is not. A mole is a pigmented skin lesion, not a hollow sac. A boil is an infected collection of pus (an abscess) behind a hair follicle, with a different cause and contents. In medical terms, it’s often called an epidermoid (sebaceous) cyst, but the straightforward, correct classification here is simply a cyst.