Tissue about the intermediate portion of the endolymphatic sac remains relatively unchanged through the second decade and in the majority of patients in succeeding decades. There are occasional small villi with loose connective tissue cores containing capillaries, and small amounts of perisacular loose areolar tissue. Changes are by fibrosis and hyalinization of the cores, with obliteration of the core capillaries, and polyp-like projection into the sac lumen, and/or focal hyalinization of the perisacular tissue. Concomitantly, there is increased perivascular tissue in the form of distended spaces adjacent to hyalinized villi or hyalinized perisacular foci. No correlation of changes was found with age, sex, or particular local or systemic disease process. "Coil"-type arteries were demonstrated in the perisacular area, with speculation on their possible role in vasoconstriction and temporary focal ischemia. Occasional thickening of capillary walls was demonstrated in the perisacular tissue.
Gussen R. Tissue Changes About the Endolymphatic Sac. Arch Otolaryngol. 1971;94(5):406–413. doi:10.1001/archotol.1971.00770070652004