Digital Myxoid Cysts: Correlation of Initial and Long-Term Response to Steroid Injections

BACKGROUND: Digital mucous cysts (DMCs) are benign myxoid pseudocysts that develop on the distal interphalangeal joint's lateral or dorsal aspects. Management consists either of a surgical approach, conservative therapy, or simple follow-up. OBJECTIVE: To correlate the initial and long-term response with clinical and ultrasound parameters in DMCs treated with intralesional steroids as first-line therapy. METHODS: A single-center prospective open-label study recruited 15 patients affected by DMCs, who had been treated with a cycle of up to 3 steroid injections at a 6 to 9 week time interval. RESULTS: At the first follow-up visit, 53.3% of patients were cleared of DMCs, achieving a complete response, whereas 46.7% experienced a >30% decrease in their DMC volume, and were considered partial responders. After 1 year of follow-up, the cure rate decreased to 40%, and the recrudescence rate was 27.3%. Clinical and sonographic characteristics that positively correlated with a maintained complete response at follow-up were as follows: young age, absence of osteophytes, low volume, complete clearance at T1, and short disease duration (p < .05). CONCLUSION: Intralesional steroid therapy is an easy approach for DMC, with minimal side effects; identifying predictive hallmarks is useful to offer a straightforward surgical treatment to patients who have nonresponder characteristics.