Which lesion is a raised, thin-walled, fluid-filled sac under the epidermis that may be larger than one centimeter?

Which lesion is a raised, thin-walled, fluid-filled sac under the epidermis that may be larger than one centimeter?

• A. Papule
• B. Cyst
• C. Vesicle
• D. Nodule

Answer: (C)

The key idea is distinguishing lesion types by content, wall structure, and size. A cyst is a closed sac with an epithelial lining that contains fluid or semi-fluid material and has a relatively thin wall. It sits beneath the epidermis and can be larger than 1 cm. That matches the description of a raised, thin-walled, fluid-filled sac under the epidermis. Vesicles are also fluid-filled but are smaller, typically under 1 cm and located at or just within the epidermis. Papules and nodules are solid, lacking a true fluid-filled cavity. So the lesion described fits best with a cyst.

The key idea is distinguishing lesion types by content, wall structure, and size. A cyst is a closed sac with an epithelial lining that contains fluid or semi-fluid material and has a relatively thin wall. It sits beneath the epidermis and can be larger than 1 cm. That matches the description of a raised, thin-walled, fluid-filled sac under the epidermis. Vesicles are also fluid-filled but are smaller, typically under 1 cm and located at or just within the epidermis. Papules and nodules are solid, lacking a true fluid-filled cavity. So the lesion described fits best with a cyst.