Tender masses that appear in the base of a finger near the palm are usually retinacular cysts. Retinacular cysts are simply ganglion cysts that come from the flexor tendon sheath of the finger. Retinacular cysts may appear rather quickly and can lead to pain when gripping objects. Fortunately, they are benign and easily treated.
The first treatment is by aspiration with a needle. This removes the fluid from the center of the cyst. If the cyst’s walls are thin, the cyst will disappear. If the walls of the cyst are thick, a smaller, less tender mass may still be palpable. If the aspiration doesn’t change the cyst at all, then the mass is probably not a cyst, and an MRI and possible surgical excision should be considered.
Aspiration is usually successful in treating retinacular cysts. However, as for ganglion cysts elsewhere, once a cyst recurs, further aspirations will probably not be effective treatment. If a retinacular cyst returns following a successful aspiration, then the options are to live with it or have it removed surgically.
The surgery is a quick outpatient procedure. The cyst is removed along with a section of the flexor tendon sheath from which it originated. The section of the sheath is removed in order to prevent recurrence, which is rare if this step is performed. This is similar to removing a section of joint capsule when excising ganglion cysts.
In conclusion, tender masses near the junction of a finger and the hand are often retinacular cysts, which are easily curable by experienced hand surgeons.