Background: Popliteal cysts are common and present as asymptomatic lumps in the medial popliteal fossa. Some have complex internal characteristics such as septa and loose-bodies. However, not all are popliteal cysts and can be aggressive. These lesions need to be differentiated by the absence of the communicating neck with the joint on ultrasound. Presence of Doppler flow of non-communicating cysts requires further evaluation on MRI, prior to performing a biopsy. Using a case series, we propose an algorithmic approach that is simple and will help identify the malignant lesions and institute appropriate management. Case-Presentation: Popliteal Cyst: On ultrasound: characteristic neck communicating with knee joint. Synovial Sarcoma: Gadolinium enhancement, with areas of low-, iso-and hyper-intense signal to fat on T2. Synovial-Osteochondromatosis: Non-mineralized: T1-low/intermediate intensity; T2-high intensity. Mineralized type: low intensity on T1 & T2. Thrombosed Popliteal Aneurysm: Lamellated appearance-high/low signal intensity on T2. MyxoidLiposarcomas: Inhomogeneous appearance; homogenous with gadolinium. Usually require a biopsy for diagnosis. Conclusion: The cystic lesions in the medial aspect of the popliteal fossa can be misdiagnosed. Our article reiterates the importance of the communicating neck that separates popliteal cysts from other mimics. We have proposed an algorithm to identify these mimics.

Objective: The objective of this study was to outline a novel unique concept of secondary impingement of the muscles, myotendons, and tendons of the rotator cuff from hypertrophy as a result of strength training exercises. Methods: In this retrospective observational study, 58 patients were referred for an magnetic resonance imaging (MRI) by the orthopedic surgeon to the radiology department over a period of 1½ years. All patients gave a history of strength training exercises and presented with clinical features of rotator cuff impingement. Results: We identified features of hypertrophy of rotator cuff muscles, myotendons, and tendons in 12 of these 58 patients. This was the only abnormality on MRI. The hypertrophy of rotator cuff muscles and tendon bulk completely filling the subacromial space to the point of overfilling and resulting in secondary compressive features. Conclusion: Rotator cuff impingement is a common phenomenon that can occur with various inlet and outlet pathological conditions. However, rotator cuff impingement may also result from muscle and tendon hypertrophy from strength training regimens. Hypertrophy of the rotator cuff can result in overfilling of the subacromial space, leading to secondary impingement, which we have termed as “pseudo-impingement.”