It may become cystic as a result of hæmorrhage or of myxomatous degeneration.
The innocent form is usually fibrous or myxomatous, and is definitely encapsulated.
myxomatous tissue is also a prominent constituent of the “innocent parotid tumour.”
myxoma myx·o·ma (mĭk-sō'mə)
n. pl. myx·o·mas or myx·o·ma·ta (-mə-tə)
A benign tumor composed of connective tissue embedded in mucus.