I have a horizontal bump under my right thumb which is growing.

Hello Anonymous,

Welcome to EmpowHER and thank you for your question.

Have you recently had an injury or trauma to that area, such as hitting your right thumb with a hammer? Does the bump feel hard or soft, as if filled with fluid?

It could be a ganglion, which is a particular type of lump which shows up next to a joint or a tendon. Inside, it is like a balloon filled with a thick liquid. It may be soft or hard, may or may not be painful, and may get bigger or smaller on its own.

This horizontal bump may also be referred to as a mucous cyst, a mucinous cyst or a synovial cyst.

Anonymous, call your primary care physician and ask if you can get an appointment to have it looked at.

Please keep us updated.

Regards,
Maryann