A nabothian cyst (or nabothian follicle) is a mucus-filled cyst on the surface of the cervix. They are most often caused when stratified squamous epithelium of the ectocervix (toward the vagina) grows over the simple columnar epithelium of the endocervix (toward the uterus).
This tissue growth can block the cervical crypts (subdermal pockets usually 2-10 mm in diameter), trapping cervical mucus inside the crypts. The transformation of tissue types is called metaplasia.
Arrows – Nabothian cysts. Sagittal T2-weighted image shows multiple uterine leiomyomas, including lesions with submucosal (M) and intramural (m) locations.
Leiomyomas usually appear as sharply marginated hypointense masses on T2-weighted images, in contrast to adenomyosis.
Nabothian cyst in the cervical region. Sagittal T2-weighted fast spin-echo MR image demonstrates irregular USL nodule (thin arrow) adjacent to posterior endometriosis of the uterus, large endometrioma, multiple uterine leiomyomas (thick arrow).
True-positive diagnosis of nodular USL involvement with endometriosis was determined at MR imaging.