Ganglion Cyst - Incidence

Incidence

Ganglion cysts are "commonly observed in association with the joints and tendons of the appendicular skeleton, with 88% "in communication with the multiple small joints of the hand and wrist" and 11% with those of the foot and ankle. They are most often found around the wrist joint, especially at the scapho-lunate area, which accounts for 80% of all ganglion cysts.

In a 2007 study of patients whose foot lumps were being surgically removed in Glasgow, 39 of 101 cases were ganglion cysts. The study replicated an earlier result that no ganglion cysts were found on the sole or heel of the foot; the authors wrote that "Although lumps in these areas may be ganglia, the surgeon should probably consider other diagnoses in the first instance." They also noted a marked female preponderance (85%) and that 11 of the other cases had been misdiagnosed as ganglion cysts before surgery.

Ganglion cysts can also occur about the knee, commonly near the cruciate ligaments, also at the origins of the gastrocnemius tendon and anteriorly in Hoffa's infrapatellar fat pad.

From their common origin at the joint or tendon, ganglion cysts can stray into a wide range of locations. Rarely, intraosseous ganglion cysts occur, sometimes in combination with a cyst in the overlying soft tissue. Very rare cases of intramuscular ganglion cysts in the gastrocnemius muscle have been reported. It is possible for the cyst to be displaced considerably from its connection to the joint. In one extreme case a ganglion cyst was observed to propagate extensively via the conduit of the common peroneal nerve sheath to a location in the thigh; in such cases surgery to the proximal joint to remove the articular connection can remove the need for a riskier, more extensive surgery in the neural tissue of the thigh. The cysts can even intrude into the spine, which can cause pain and dysesthesia in distant extremities.

It has recently been proposed that cystic adventitial disease, in which a cyst occurs within the popliteal artery near the knee, may occur by an articular mechanism, with a conduit leading from the joint, similar to the development of ganglion cysts that spread within the peroneal nerve.