These are cystic lumps that arise from the end joint of fingers and thumb. It starts as a small lump and gradually increases in size causing the skin to become very thin and translucent. Sometimes it ruptures discharging clear slimy fluid. After discharge it usually subsides only to recur again. The cause of these cysts is an underlying arthritic joint which forms excess fluid which pushes out forming these cysts. It is for this reason that they can recur.
The cysts can be painful especially when knocked and large ones are unsightly. The lumps can reach a size of a pea or slightly bigger but never get very large. Since it arises close to the base of the nail it can cause nail abnormalities such as indentation or grooves.
Small lumps if they are not too troublesome can be left alone. Symptomatic ones can be treated by aspiration or puncture with a needle to disperse fluid and cause it to scar and heal. However there is a high recurrence rate. The standard treatment for these cysts is surgical removal which is done under local anaesthetic. Simple excision is usually sufficient. When the skin is much thinned, the cyst is removed together with the skin and a small skin flap is made to close the wound. These methods are very effective and recurrence rates are low.
The risks of operation are infection and recurrence of cyst.
Finger is bandaged which is removed by about 48 hours and small plaster is applied to the wound. Movements and function are encouraged but the wound should be kept clean and dry until sutures are removed. Recovery is swift and wound is healed by 10 to 14 days when sutures are taken out.
FRCS (Trauma & Orth)
Consultant Trauma and Hand Surgeon