PAX8 and cyst: This is supported by the observation that the uterine cyst was lined by a single layer of flattened cuboidal to columnar epithelial cells; cyst epithelia were not associated with the endometrial cavity, glands, or stroma; the cyst walls were located immediately subjacent to or embedded in the outer myometrium; and the cyst epithelia were positive for antibodies for HBME-1 and cytokeratin 5/6 and negative for antibodies for PAX8 and GATA3.