Figure 1. Anteroposterior radiograph of hand.
Figure 2. Photo of affected finger.
A 75-year-old woman presents with a cyst on her right index finger that has been present for 3 weeks. She denies having pain in the finger or having an injury. Anteroposterior radiograph is taken of the hand (Figure 1). The cyst is small, clear, firm, and appears directly over the distal interphalangeal (DIP) joint (Figure 2). The patient wants to pursue a treatment option with the lowest rate of recurrence.
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Ganglions, including mucous cysts, account for 60% of hand and wrist tumors.1 Although ganglions affect all age groups, mucous cysts are typically seen in older patients.1 The patient in this case has a mucous cyst that is associated with underlying DIP arthritis. The mass is classically firm and transilluminated by a light test. The most commonly affected fingers are the index and long finger.1
The cyst was formed by underlying arthritis at the DIP joint, which creates swelling and fluid buildup. A stalk creates a connection between the intra-articular space and the cyst. In general, mucous cysts do not require treatment. However, if the skin thins and the cyst looks likely to rupture, aspiration or surgery is considered. Underlying arthritis, but not a cyst, may be a source of pain; thus, removing the cyst will not relieve pain.1
Aspiration of the cyst alone has a high recurrence rate in the range of 50% to 70%; this compares with debridement and surgical excision of the stalk, which has a 2% recurrence rate.1 Surgery involves removal of the cyst including the stalk and any visible dorsal osteophytes at the DIP joint. Removal of the stalk and osteophytes helps reduce the recurrence rate.2 Chronic mucous cysts drainage and painful DIP arthritis are generally treated with a DIP fusion. Fusion is not indicated if the finger is not painful.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
1. Thornburg L. Ganglions of the hand and wrist. J Am Acad Orthop Surg. 1999;7(4):231-238. doi:10.5435/00124635-199907000-00003
2. Kleinert HE, Kutz JE, Fishman JH, Mccraw LH. Etiology and treatment of the so-called mucous cyst of the finger. J Bone Joint Surg Am. 1972;54(7):1455-1458.