A mycetoma is a discrete mass of intertwined hyphae, usually of an Aspergillus species, matted together by mucus, fibrin, and cellular debris colonizing a cavity, usually from prior fibrocavitary disease (eg, tuberculosis or sarcoidosis). A mycetoma may move to a dependent location when the patient changes position and may show an air crescent sign. CT scans may show a spongelike pattern and foci of calcification in the mycetoma. [from
HPO]