Introduction
Thecal cyst usually appears around the joint, especially on the dorsal side of the wrist joint. The main manifestations are painless, hard and small semi-spheroid lumps. The external membrane of the cyst is fibrous tissue and the internal membrane is white and slippery. The cyst is full of whitish colloidal liquid. Thecal cyst is similar to wrist tendon tumor in TCM due to stagnation of qi, accumulation of fluid into phlegm and coagulation in the meridians.

Syndrome differentiation
Local pathological change is semi-spheroid lumps that are smooth in surface and bear no adhesion with the skin. The smaller ones are the size of soy beans and are hard in texture. The larger ones are the size of dove eggs, appears mobile under pressure. There is no pain, only occasional sense of aching, distension and weakness in excessive movement.

Treatment
Prescription: Local cyst.

Performance: The thick needle of No. 28 is used to puncture 1 cun vertically from the top of the lump and then puncture obliquely the four sides of the lump with rotating technique. The needle is retained for 15 minutes. When the needle is withdrawn, the needling hole is enlarged by swaying the needle.  The needling hole is squeezed to press out colloidal liquid. After needling, the affected part is bandaged with pressure for 3 - 5 days.