A Large Posteromedial Parameniscal Cyst Masquerading a Baker's Cyst: An Unusual Presentation

Abstract

Introduction: Meniscal cysts are rare and strongly associated with a horizontal meniscal lesion. Arthroscopic partial meniscectomy of the meniscus with intra-articular cyst drainage has become the standard of care for small cyst; however, sometimes large cyst requires open excision.

Case presentation: We report a case of a large symptomatic medial parameniscal cyst in 52-year-old female which was clinically misdiagnosed as Baker's cyst. The patient had swelling over the posteromedial aspect of the right knee with difficulty and pain on squatting. Magnetic resonance imaging (MRI) reported horizontal tear in the posterior horn of medial meniscus and parameniscal cyst adjacent to medial meniscus with features of early osteoarthritis of the knee. She was successfully treated with open excision and repair of the defect of the cyst along with arthroscopic partial medial meniscectomy.

Conclusion: This case highlights the importance of MRI in diagnosis and planning and the use of a combined approach for successful management of large parameniscal cyst.

Keywords: Arthroscopy; Baker’s cyst; MeSH terms: Parameniscal cyst; Medial meniscal cyst; Medial meniscus; arthroscopic meniscectomy; open excision.

Figure 1a

An axial slice T2-weighted MR image shows a meniscal cyst (Black arrow), demonstrated by the hyperintense signal adjacent to the meniscus.

Figure 1b

T1-Weighted coronal image showing a hypointense large medial meniscal cyst (white arrow) extending around the medial collateral ligament into the soft tissues.

Figure 2

Intraoperative image of cyst (black arrow).