Rare Ganglion Cyst of the First Metatarsophalangeal Joint: A Case Report.

Ganglion cysts are common benign lesions arising from joint capsules or tendon sheaths, but their occurrence in the first metatarsophalangeal (MTP) joint is extremely rare. Preoperative diagnosis of subcutaneous tumors in this region can be difficult, as imaging findings are often nonspecific and biopsy may be avoided due to the risk of nerve or vessel injury. We report the case of a woman in her 70s who presented with a slowly enlarging subcutaneous mass on the medial aspect of the right first MTP joint. MRI and ultrasound suggested a cystic lesion but failed to confirm continuity with the joint capsule. During surgery, jelly-like contents were identified, confirming the diagnosis of a ganglion cyst. Complete excision including the stalk was performed, and no recurrence has been observed after six months of follow-up. This case demonstrates that intraoperative findings can be crucial for establishing a diagnosis and ensuring complete excision when preoperative evaluation is inconclusive. Dermatologists performing minor surgery should recognize the importance of intraoperative assessment when managing diagnostically challenging subcutaneous tumors.