Musculoskeletal Ultrasound Diagnosis of Symptomatic Hoffa's Fat Pad Ganglion Cyst Successfully Managed Nonoperatively: A Case Report.

Ganglion cysts (GCs) can arise from a variety of different areas, but those arising from Hoffa's fat pad in the knee are relatively rare. A number of different types of cysts are also found in the knee, including meniscus cysts, proximal tibiofibular cysts, and cruciate ligament ganglion cysts. In this case report, a 54-year-old female presented with left knee pain and swelling for eight weeks. In-office musculoskeletal ultrasound (US) was used to diagnose a Hoffa's fat pad ganglion cyst and aid in targeted steroid injection. The patient was followed up 21 weeks after the injection. She was pain-free, and US findings showed the cyst had significantly decreased in size. This case shows how musculoskeletal ultrasound, a relatively inexpensive diagnostic modality, can be used to accurately diagnose the cause of knee pain, guide an in-office procedure for the treatment of Hoffa's fat pad ganglion cyst, and aid in monitoring.