Tibial Periosteal Ganglion Cyst: A Rare Case of Non Traumatic Leg Swelling

Soft tissue ganglion cysts are most commonly seen around the wrist and arise from myxomatous degeneration of periarticular connective tissue. A lesion produced by the mucoid degeneration and cyst formation in the periosteum of long bones is called a “periosteal ganglion”. These are commonly found in the lower extremities. In this article, we present a case of a 50-year-old female who presented with swelling and dull aching pain over the upper 1/3rd of the left leg for two months. MRI showed a lobulated cyst-like mass that was hypointense to muscle septation with a size of 14×12 mm. The patient underwent excision of the lesion, which was diagnosed as a periosteal ganglion cyst through imaging and confirmed by excision biopsy. Periosteal ganglions are benign cysts with a good prognosis, and they should be considered as a differential diagnosis when encountering pretibial soft tissue swelling.