Recurrent Intra-articular Lipoma of Ankle Joint; A Rare Case Report

Most soft-tissue tumors in the foot and ankle are benign. While lipomas are the most prevalent type of soft-tissue tumor, intra-articular lipomas are exceptionally rare. Most documented intra-articular lipomas involve the knee joint, and there have been only a few case reports of an intra-articular lipoma in the ankle.

We present the case of a 77-year-old woman with a recurrent, progressively enlarging ankle mass that had persisted for 19 years following surgery 15 years prior. At present, the swelling is limiting her range of motion. On examination, a firm, non-tender mass was observed on the medial side of the left ankle joint without any signs of inflammation. The mass was non-compressible, immobile, and did not transilluminate. The clinical diagnosis suggested a soft-tissue ganglion. A radiograph showed soft-tissue opacity over the anteromedial aspect of the tibiotalar joint. Magnetic resonance imaging (MRI) revealed a well-defined, multilobulated, encapsulated lesion at the tibiotalar joint's medial side, with intra- and extra-articular components. The patient underwent surgical excision of the tumor, and histopathological examination confirmed the presence of mature adipose tissue consistent with an intra-articular lipoma with fibrous septa. At the follow-up visit, the patient reported a complete resolution of symptoms and had no further complaints.

An intra-articular lipoma of the ankle is an extremely rare tumor. Clinical examination is essential in diagnosing the lesion. MRI is primordial for both differential diagnosis and preoperative planning. Depending on the tumor size, an excision can be performed through open arthrotomy or arthroscopy.