Nabothian cysts of the cervix are common, benign, often asymptomatic cystic structures formed when squamous cells of the ectocervix grow to cover columnar cells of the endocervix. The columnar cells secrete mucoid material that becomes entrapped, forming a spherical structure in the cervical stroma.
Nabothian cysts typically range from a few millimeters to 1 or 2 cm in size, and multiple cysts may exist simultaneously. They are easily identified on visual examination of the cervix, can sometimes be palpated, and appear translucent, opaque or yellowish in color. Ultrasound easily confirms a diagnosis in most cases.
Looking for Cervical Cysts in a Standard Ultrasound Exam
A standard pelvic ultrasound exam should include the evaluation and documentation of cervical findings. Clinicians should record the description of any endocervical findings, such as polyps and fluid, and the presence of any masses or cysts.
On ultrasound, a typical nabothian cyst appears as a single round lesion with smooth borders. The cyst lacks any solid components, and posterior acoustic enhancement is possible. Assessing the uterus and ovaries with ultrasound can help confirm the benign nature of an incidental nabothian cyst.
While nabothian cysts are benign, other cervical masses may not be. Other cyst-like cervical lesions include mesonephric cysts — microscopic remnants of the Wolffian duct — and cervical adenosis, which may occur in women after exposure to diethylstilbestrol (DES) in utero. Cervical adenosis is usually found in association with vaginal adenosis and does not require excision unless the patient is symptomatic.
Differentiating Between Nabothian Cysts and Cervical Abnormalities
Identifying nabothian cysts may be challenging in patients with congenital cervical anomalies, where the appearance of the cervix is already abnormal. Cervical myomas undergoing cystic degeneration or adenoma maligna (a subtype of mucinous adenocarcinoma of the cervix) can, rarely, be confused with nabothian cysts. These conditions should be included in the differential diagnosis.
Any unexpected physical symptoms, such as a watery discharge, or suspicious findings during a physical or ultrasound exam should prompt a Pap smear, colposcopy or further imaging if necessary.
3D ultrasound allows for a more complete visualization of cervical lesions. On ultrasound, a malignant lesion is typically multicystic, can contain solid components and may be located deep in the stroma of the cervix. If Doppler is available, it will reveal if the cyst is vascularized. If the cervical cyst appears benign but evidence of endometrial hyperplasia or concerning ovarian masses are found, further evaluation of the cervix may be wise.
Treating Benign Cystic Cervical Lesions
Treatment for symptomatic benign cystic lesions of the cervix is fairly simple. Incision and drainage, ablation or excision provides relief in most cases. Hysterectomy is usually unnecessary, even when nabothian cysts larger than 4 cm are found. Patients are often able to heal rapidly after these minor procedures, and follow-up exams reveal a normal cervical appearance.
Remind your patients that regular OB/GYN assessments, including transvaginal ultrasound, are key for monitoring their gynecological health. Ultrasound can help clinicians quickly and effectively differentiate a malignant cervical mass from a harmless one.
