A ganglion cyst is a small sac of fluid that forms over a joint or tendon (tissue that connects muscle to bone). Inside the cyst is a thick, ...MenuNewsReferenceSlideshowsQuizzesVideosQuestions&AnswersWebMDRxSavingsCardCoronavirus(COVID-19)CBDOilKetoDietHepatitisCDiabetesWarningSignsRheumatoidArthritisMorning-AfterPillBreastCancerScreeningPsoriaticArthritisSymptomsHeartFailureMultipleMyelomaTypesofCrohn'sDiseaseAtoZGuidesReferenceMenuMedicallyReviewedbyHansaD.Bhargava, MDonAugust24,2020InthisArticleWhatIsaGanglionCyst?GanglionCystSymptomsGanglionCystCausesandRiskFactorsGanglionCystDiagnosisGanglionCystTreatmentNextStepsFollow-UpGanglionCystPreventionGanglionCystOutlookWhatIsaGanglionCyst?Aganglioncystisasmallsacoffluidthatformsoverajointortendon(tissuethatconnectsmuscletobone).Insidethecystisathick,sticky,clear,colorless,jellylikematerial.Dependingonthesize,cystsmayfeelfirmorspongy.Ganglioncysts,alsoknownasbiblecysts,mostcommonlyshowuponthebackofthehandatthewristjointbuttheycanalsodeveloponthepalmsideofthewrist.Theycanalsoshowupinotherareas,butthesearelesscommon:Thebaseofthefingersonthepalm,wheretheyappearassmallpea-sizedbumpsThefingertip,justbelowthecuticle,wheretheyarecalledmucouscystsTheoutsideofthekneeandankleThetopofthefootGanglionCystSymptomsSymptomsofaganglioncystcaninclude:Asoftbumpormassthatchangessizebutdoesn’tmove.Swellingthatmayappearovertimeorsuddenly.Itmaygetsmallerinsizeorevengoawayandcomeback.Onelargecystormanysmalleronesmaydevelop,buttheyareusuallyconnectedbydeepertissue.Somedegreeofpainispossible,especiallyafteracuteorrepetitivetrauma,butmanyaren’tpainful.Painmaybechronicandgetworsewithjointmovement.Whenthecystisconnectedtoatendon,youmayfeelasenseofweaknessintheaffectedfinger.Thebelow imageshowsatraumaticganglioncyst.Thispersoncametotheemergencydepartmentwithapainfulbumpafterthewristwashitbyacardoor.The imagebelowshowsthejellylikefluidtakenfromthecystintheaboveimage.Itspresenceconfirmsthediagnosisofaganglioncyst.Anultrasoundimagebelowshowsthegangli