Ganglion cysts are very common masses (lumps) that sometimes grow in the hand and wrist. The cysts are generally found on the top of the wrist, sometimes on the palm side of the wrist, the end of the joint finger, and at the base of a finger. Although there is usually no specific cause for ganglions, there has often been an injury before the appearance of a cyst. These cysts can be painful, especially when they first appear, and with constant or strenuous use of the hand or wrist. Ganglions often change in size and may disappear completely.

Region Affected: Hand and Fingers | Wrist

Links:
Ganglion Cysts - Handsurgery.com

Dupuyten's contracture is a disease that can lead to limited use of your hand.

This may happen when certain tissue in the palm thickens. While it doesn't always cause pain, it can make it hard to straighten your fingers. Signs and symptoms include a hard lump forming across your palm, inability to place your palm flat on a surface, scarlike bands forming across your palm, and hand pain (less common.). Symptoms usually appear in 50 to 60 year-old men whose families come from northern European countries.

Region Affected: Hand and Fingers

Links:
Dupuytren's Disease - SCOI