Paralabral cyst of the hip leading to common femoral vein compression

Identification of causes for venous outflow obstruction often requires multimodal evaluation. Anchoring bias can challenge recognition of rare pathophysiology, even when common imaging findings are found in uncommon locations. In this review, we present a case of a female patient with several months of right lower extremity edema. Initial misinterpretation of ultrasonography led to the diagnosis of deep vein thrombus as the instigating factor for which the patient was unsuccessfully treated with oral anticoagulation. Cross-sectional imaging and venography were employed showing external compression of the common femoral vein by a cystic structure. Subsequent percutaneous aspiration led to immediate improvement in venous flow by venography. Advanced MR imaging and arthrography were employed showing a labral tear with recurrence of a prominent paralabral cyst compressing the common femoral vein. The patient was managed with definitive arthroscopic cyst decompression and labral repair leading to complete resolution of the patient’s presenting symptoms. This case underscores the American College of Radiology (ACR) appropriateness criteria recommending cross-sectional imaging when patients present with inconclusive vascular ultrasound or suspected iliofemoral thrombus. It also adds to well established data that high recurrence rates of paralabral cysts are noted after percutaneous aspiration while lower recurrence is noted with arthroscopic labral repair and cyst decompression.