Ultrasonographic characteristics of two common musculoskeletal lesions, ganglion cysts (GCs) and synovial cysts (SCs) are presented through a review of the literature. Although similar in many ways, these two lesions display different morphostructural characteristics justifying, in our view, their descriptions as separate entities. Mainly different from an anatomopathologic point of view, they also differ in their potential therapeutic implications. A symptomatic GC, refractory to conservative therapy, may require surgical excision of the cyst itself. For SC, therapy should primarily be oriented toward identifying and correcting the often coexisting intra-articular disease instead of only targeting merely its consequence, the SC.