Sonographic appearances of meniscal cysts

PURPOSE: This study was conducted to define the sonographic appearances of cysts of the tibial menisci. METHODS: Thirteen cases of meniscal cyst, proven by magnetic resonance imaging (MRI), were assessed using high-resolution sonography, and results of the 2 imaging modalities were correlated. RESULTS: Seven meniscal cysts were lateral to the joint line, and 6 were located medially. MRI showed all 13 cysts to be associated with a tear of the adjoining meniscus. On sonograms, cyst size varied from 9 to 56 mm. Echotexture varied from uniformly hypoechoic or hypoechoic with echogenic septa to heterogeneously hyperechoic. Septated cysts were demonstrated by MRI and sonography. CONCLUSIONS: Because of their diverse echo patterns, meniscal cysts may be easily mistaken for soft-tissue tumors, ganglions, or other lesions, which may result in surgery being inappropriately recommended. This is particularly true in the case of echogenic cysts. The cardinal sonographic characteristic of a meniscal cyst is its continuity with the meniscus, not its echotexture.