A tumor is a swollen
Mass of tssue that does not belong n the place that it is.
In the hand or in any other part of the body a tumor is caused by an abnormal bit if tissue growing where it does not belong. A ganglion is the most common soft tissue tumorof the hand. Other common benign tumors are giant cell tumor of tendon sheath .
Benig tumors are very common in the hand, dangerous one do occur but a lot less frequenl.