Recurrent finger swelling

A 56 year old female presented to her primary care physician with a painless finger mass. She first noticed the mass about 7 years ago and it had been growing slowly since that time. Her former primary care physician had removed the mass about 5 years prior. She recalled being told at that time that it was a “ganglion cyst.” The mass had since returned and grown back to its former size. It was not frankly painful, though it did feel tight and often got in the way of daily tasks. She denied any numbness or tingling in her finger, and denied any warmth, redness or swelling in her other joints. Her past medical and family histories were non-contributory, including no history of gout, autoimmune disease, or cancer. Physical examination revealed a non-tender, soft, well circumscribed mass on the extensor aspect of the right fifth digit, just proximal to the base of her fingernail (Figure 1A). The mass was approximately 2cm x 2cm and did not transilluminate (Figure 1B). The mass was fluctuant and encapsulated. There was no swelling or effusion in the hand, fingers, or joints. Neurologic exam showed no sensory or motor deficits. The radiograph showed a non-invasive soft tissue mass on the dorsal aspect of the fifth distal phalanx (Figure 1C). Incisional biopsy was performed. The mass was found to be composed of non-encapsulated fatty tissue, and extended to the extensor tendon sheath. The patient was referred to hand surgery for a definitive excision.