TITLE:
Radiological Mimics of Popliteal Cysts: An Algorithmic Approach Using US and MRI to Identify the Potentially Malignant Lesions: Case Series
AUTHORS:
Andrae Blanchard, Asad A. Naqvi, Zain Badar, Hema Choudur
KEYWORDS:
Popliteal Cyst, Malignant Lesions, Mimics, Algorithmic Approach
JOURNAL NAME:
Open Journal of Clinical Diagnostics,
Vol.6 No.2,
June
2,
2016
ABSTRACT: 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. Myxoid-Liposarcomas:
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.