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1441 - Strangulated Ganglion Cyst Mimicking a Simple Baker Cyst: A Case Report

Friday, February 28, 2025

5:00 PM - 6:30 PM MST

Presenting Author(s)

DL

Deanna Lewis, MA

OMS-3
Lake Erie College of Osteopathic Medicine
Rochester, New York, United States

Co-Author(s)

MM

Margaret O. Martinez, DO

Resident Physician
NYU Rusk Rehabilitation
River Vale, New Jersey, United States
TE

Tracy Espiritu McKay, DO

Clinical Assistant Professor
NYU Rusk Rehabilitation
New york, New York, United States

Case Diagnosis: Ganglion Cyst Adherent to Popliteal Artery

Case Description: A 64-year-old female with a history of partial medial meniscectomy presents with several months of achy right knee pain with no inciting event. Physical exam was significant for fullness of the posterior knee. Patient was scheduled for aspiration and corticosteroid injection. 9mL of fluid was removed under ultrasound guidance. Despite this, pain and fluid returned within a week. An MRI subsequently revealed a multiloculated ganglion cyst extending from the semimembranosus and exerting pressure on the popliteal artery, measuring 2.9 x 2.1 x 3.6 cm. A second attempt to aspirate the cyst, one month later, was aborted after withdrawing 3cc of fluid, followed by dark venous blood. Due to the cyst's location and complexity, the patient was referred to oncological orthopedic surgery for removal of the ganglion cyst. During surgery, the cyst was found to be adherent to the right popliteal artery.

Discussions: Ganglion cysts are typically benign masses that originate from herniation of dense connective tissue containing mucinous, gelatinous fluid. They classically occur on the dorsum of the wrist. This case represents a rare case of a ganglion cyst in the popliteal fossa mimicking a Baker cyst. This case is further complicated by blood vessels strangulating the cyst. Blind Baker cyst aspiration is sometimes performed; however, due to this added layer of complexity, ultrasound guidance was essential in this case to allow for the initial cyst drainage and avoidance of blood vessels.

Conclusions: Ultrasound-guidance is imperative for physiatrists during aspiration procedures including suspected Baker cysts. In rare cases such as this, a fullness of the posterior knee may actually represent a ganglion cyst. Ultrasound-guidance has become the standard for aspirating cysts due to improved accuracy in visualizing variant cysts that adhere and compromise neurovascular bundles.