Distal interphalangeal joint (DIPJ) ganglion, commonly called a mucous cyst, or Dorsal digital ganglion cysts
Distal Interphalangeal joint ganglion commonly present as lumps on the dorsum of the finger at one or other side of the joint.
At the DIPJ they are commonly seen adjacent to the nail fold and are commonly called mucous / mucus cysts. They tend to occur in older people and may be associated with underlying joint degeneration. The lump can fluctuant in size. If they grow over the germinal matrix they can cause nail deformity which can become permanent (groove or nail split).
Symptoms include pain. If joint stiffness is present this is an indication that there is underlying joint pathology and an x-ray should be considered.
The lumps can burst. The skin overlying can be thin and translucent. These factors can allow infection to develop and track deep into the joint.
Do not attempt aspiration or bursting of mucous cysts, as this can lead to septic arthritis.
Surgical excision is indicated for mucous cysts of large size, mucous cysts with thin skin or history of bursting, or causing nail deformity. Surgery is performed as a day case under local anaesthetic, and can require a couple of weeks off work. Recurrence is possible after excision.
