Review some of the most common etiologies of popliteal fossa masses. Understand the anatomical features and the radiological appearance of the different lesions.

There is a wide variety of lesions that can be identified in the popliteal fossa, ranging from benign entities to malignant ones. Understanding the imaging characteristics and anatomical pearls of the different lesions is essential to enable the radiologist to formulate relevant differential diagnoses and help guide appropriate management. A diagnostic approach was proposed by Shah A et al which uses anatomical references to filter the different diagnosis (figure 1).

We performed a retrospective review of cases of popliteal masses in 2016 at our institution and selected key X-ray (Xr), ultrasound (US), computed tomography (CT) or magnetic resonance (MR) images of the various entities. For literature review, we have searched indexed publications using Medline as the scientific repository for current data regarding this particular area of interest. INTRA-ARTICULAR – CYSTIC LESIONS A.1. POPLITEAL CYST Popliteal cyst, or Baker’s cyst, is the commonest posterior knee mass. It is a painless fluid-filled mass that represents a distention...

We have found several benign and malignant entities that can occur in the popliteal fossa. Although histology is often required for definitive diagnosis (especially for malignant lesions), awareness of the different appearances and locations of the various aetiologies of popliteal fossa masses allows the radiologist to narrow the differential diagnosis avoiding unnecessary additional investigations.

A diagnostic approach to popliteal fossa masses. Shah A, et al. Clinic Radiology (2016) Pigmented Villonodular Synovitis and Giant Cell Tumors of the Tendon Sheath: Radiologic and Pathologic Features. Jaume Llauger, Jaume Palmer, Núria Rosón, Rosa Cremades, Silvia Bagué. American Journal of Roentgenology 1999;172: 1087-1091. Aggressive Fibromatosis: MRI Features with Pathologic Correlation. Justin C. Lee, J. Meirion Thomas, Simon Phillips, Cyril Fisher, Eleanor Moskovic. AJR January 2006; 186:247–254. Imaging of Musculoskeletal Fibromatosis. Mark R. Robbin,MD, Mark D. Murphey, MD,H. Thomas Temple, MD,et al. Radigraphics May...