SNOMED (like various specialized medical sources) makes a distinction between 240205003 | Synovial cyst (disorder) and 445008009 | Ganglion cyst (disorder). Both are children of 441457006 | Cyst (disorder).
ICD-11 gives this definition of “ganglion” (translated simply by “kyste” in French, so cyst, which is a wrong translation):
“This is a nodular tumour-like lesions or mucoid flesh, arising from tendon sheaths, ligaments, or joint capsule, especially of the hands, wrists, or feet. They are not true cysts as they lack epithelial wall. They are distinguished from synovial cysts by the lack of communication with a joint cavity or the synovial membrane.”
I cannot find any official translation of ganglion cyst in French, as most medical sources consider it’s a synonym of synovial cyst.
Not much help, but in Swedish we use ganglion (stand alone, ny cyst added afterwards in ICD-11, but in Snomed we added cyst), Synovial cyst is syniovalcysta.
In French, strictly speaking, the adjective “ganglionnaire” only refers to lymps nodes or, in very specific cases, nerve ganglions. But maybe there’s an extension of that meaning in clinical settings so that clinicians can identify this type of false cyst and distinguish it from a synovial cyst; I’ll look into it. Thank you.
Also, ganglion is the colloquial synonym of lymph node (medical term: noeud lymphatique), so it’s not the right equivalent in French.
Just adding a couple references explaining the differences between a ganglion cyst and a synovial cyst. I think this is mostly a French translation problem, as you seem to have equivalents for each in your language.