From Trauma To Tumor: An Ankle-deep Investigation

HISTORY: A 66-year-old male presented to Sports Medicine with chronic left ankle pain and swelling. The left ankle swelling started around ten years ago and began as a marble-sized mass before more rapidly growing in the last four years. There was no specific inciting injury or event that triggered the swelling at the time. He has a history of multiple prior left ankle injuries though, including a fractured left ankle growth plate at 11 years old while sliding into second base during Little League, a broken left ankle at 23 and 28 while moving a fridge, and around five left ankle sprains. All his left ankle injuries were non-operatively managed. For exercise, he grew up avidly playing baseball, basketball, and football, sticking mainly to one to two-mile walks in his later years. The patient had been managing the intermittent pain with ice and Biofreeze. He denied numbness, focal weakness, fevers, or erythema. PHYSICAL EXAMINATION: Physical exam revealed a golf ball-sized swelling in the left anterior ankle with mild tenderness and talocrural joint stiffness. Ankle joint bony anatomy felt thickened. Anterior drawer and talar tilt tests were negative. 5/5 plantarflexion/dorsiflexion. Sensation was intact with no cranial nerve deficits. DIFFERENTIAL DIAGNOSIS: 1. Left anterior ankle soft tissue mass 2. Tenosynovial giant cell tumor 3. Atypical lipomatous tumor TEST AND RESULTS: X-ray: No fractures; noted 2.7 x 5.0 cm mass in the anterior ankle. - Ultrasound: Mixed echogenic signal, no fluid or cystic structure. - MRI: 5.4 x 2.2 x 3.8 cm mass abutting anterior tibialis and extensor hallucis longus tendons. - Biopsy: Spindle cell lipoma confirmed, with RB1 stain loss and negative MDM2 amplification on FISH. FINAL WORKING DIAGNOSIS: Spindle cell lipoma (SCL) TREATMENT AND OUTCOMES: The patient’s SCL was excised successfully. He resumed walking three days post-op, albeit at reduced distances. At two months, he showed adequate recovery but had decreased left ankle dorsiflexion range, plantarflexion strength, and single-leg balance. A tailored home exercise program was provided to address these areas. The patient will continue gradually increasing his walking distance and follow up with Sports Medicine as needed.