Correct answer:

This is a painless, subcutaneous, cystic swelling commonly found on the pulps of the fingers, attached neither to skin nor to the deeper structures. It usually follows a puncture injury (e.g. from a rose thorn) with consequent implantation of epithelial cells into the subcutaneous tissues. The cyst typically contains a white, greasy material, which results from degeneration of the desquamated cells. An old healed scar over the cyst may help confirm the diagnosis.