A nabothian cyst (or nabothian follicle) is a mucus-filled cyst on the surface of the cervix. They are most often caused when the stratified squamous epithelium of the ectocervix (portion nearest to the vagina) grows over the simple columnar epithelium of the endocervix (portion nearest to the uterus). This tissue growth can block the cervical crypts (subdermal pockets usually 2–10 mm in diameter), trapping cervical mucus inside the crypts.
Nabothian cysts (also called mucinous retention cysts or epithelial cysts) are a common and benign gynecological condition in reproductive age without clinical significance. These cysts are at the squamocolumnar junction (SCJ) of the uterine cervix, which is the targeted anatomical area of brush sampling at the time of cervical screening cytology. They are filled with mucus, but they may also contain proteinaceous material, neutrophils, or neutrophil debris. These cysts usually appear superficially and are easily recognized during colposcopy examination.[rx]
Multiple and large cysts, situated in the cervical stroma, can induce considerable enlargement of the cervix, which can lead to symptomatology. Other causes of these large cysts include cystic degeneration of uterine leiomyoma and congenital uterine cysts such as mesonephric and paramesonephric cysts and cystic adenomyosis.[rx]
In most cases, nabothian cysts occur when new tissue regrows on the cervix after childbirth. This new tissue blocks the openings of the cervix’s nabothian glands, trapping their mucous secretion in tiny pockets under the skin. Nabothian cysts are a normal finding on the cervix of women who have had children. They also are seen in menopausal women whose cervical skin has thinned with age. Less often, nabothian cysts are related to chronic cervicitis, long-term infection of the cervix.
Nabothian cysts also are called nabothian follicles, epithelial inclusion cysts, and mucinous retention cysts.
Causes of Nabothian Cysts
The squamous epithelium of the uterine cervix proliferates, covering the columnar epithelium of the endocervical glands; this takes place when it gets chronically inflamed as a result of the healing process of chronic cervicitis, or as part of the physiological metaplasia. The columnar epithelium secrets mucous, which then forms retention cysts, which are the Nabothian cysts. Although the cysts are often small, only a few millimeters in diameter, they sometimes may reach 4 cm or more.[rx]
The cervix is lined with glands and cells that release mucus. The glands can become covered by a type of skin cells called squamous epithelium. When this happens, the secretions build up in the plugged glands. They form a smooth, rounded bump on the cervix. The bump is called a nabothian cyst.
Symptoms of Nabothian Cysts
Small nabothian cysts do not usually cause any symptoms. However, larger nabothian cysts may cause:
- pelvic pain
- a full or heavy feeling in the vagina
- irregular periods
- Each nabothian cyst appears as a small, white raised bump.
- Nabothian cysts do not cause any symptoms unless they become very large.
Diagnosis of Nabothian Cysts
During smear taking, superficial Nabothian cysts may get busted by the spatula; the mucoid content could stick to the brush and be smeared upon the slides in conventional cytology or be mixed in with the preserving solution of the liquid-based cytology (LBC) preparations. In LBC, mucus is rarely present, as it dissolves in the preserving solutions and centrifugation preceding the slide preparation. Macroscopically, a Nabothian cyst would appear as a cervical cyst containing mucinous liquid (2). Infrequently, mucus contained in Nabothian cysts may become impregnated by neutrophils, where its granular appearance will be visible on LBC slides. It is a well-established fact that Nabothian cyst content is identifiable on conventional Pap smears and that it can be misguided for tumor diathesis pattern that is associated with invasive carcinoma.[rx]
Microscopically, Nabothian cysts are lined by a single layer of columnar epithelium or flattened epithelium without cellular mitosis or atypia.[rx]
History and Physical
Nabothian cysts are often asymptomatic and discovered incidentally during colposcopy examination. However, if the cyst is large and complex, it may be mistaken for malignancy or a tumor, as it may cause symptoms such as dyspareunia, pelvic pain, pressure symptoms if it does press on an organ, for example, if it presses on the rectum it may lead to abnormal defecation and tenesmus, urinary retention, amenorrhea, and lower abdominal pain.[rx][rx][rx]
Evaluation
Transvaginal ultrasound and Magnetic Resonance Imaging (MRI) can help establish a diagnosis of Nabothian cysts. MRI can differentiate between endophytic and exophytic growth, and between normal and abnormal conditions. The Nabothian cyst appears characteristically as high T2 signal intensity on MRI.
If cancer is suspected and MRI can’t exclude it, biopsy, conization, and endocervical curettage are efficient investigative tools to be used.
Sadly, despite the use of these modern diagnostic techniques, exploratory laparotomy and hysterectomy may still be required in the case of uncommonly large and deep intracervical cysts when malignancy cannot be ruled out.[rx]
Transvaginal ultrasonography and magnetic resonance imaging are the most useful imaging methods for cervical cystic lesions. HPV infection is the most important factor which can cause cervical malignancy and premalignant lesions. In women, between 30-65 years of age HPV-DNA testing, is used as a screening test in Turkey. In this research, the aim is to examine whether there is a connection between Naboth cysts and HPV infection in the cervix. During the examination, the swab sample required for HPV PCR testing will be taken. The number and size of Naboth cysts with vaginal USG will be noted. If the patient had colposcopy / LEEP (Loop Electrosurgical Excision Procedure), the result will be investigated and noted.
Treatment of Nabothian Cysts
Nabothian cysts usually require no treatment and frequently resolve on their own.[rx] Cryotherapy has been used to treat nabothian cysts but is rarely necessary.[rx] Very rarely a cyst may be so large that it prevents a clinician from performing a pap smear, in which case the clinician may puncture the cyst with a needle and drain it.[rx] If nabothian cysts occur with chronic cervicitis (inflammation of the cervix) then the underlying cause of the inflammation must be treated.[rx]
Nabothian cysts require no treatment if they are asymptomatic and carry no malignant possibility. Therapy is advocated in symptomatic cases with pain, or when malignancy cannot be excluded. If required, treatment mainly consists of drainage. The main objection to surgical intervention is the risk of scar tissue, which itself may cause pain in the future.[rx]
In cases of an obstructed passage of labor, simple drainage is also used to allow normal vaginal delivery. If the diagnosis can’t be reached, or in cases of deep cysts or large symptomatic cysts, excision is demanded to evaluate the histopathology and exclude other cervical tumors and adenoma malignum.[rx]
Usually, no treatment is needed. However, in some cases, your gynecologist may choose to remove the cyst. This can be done one of two ways:
- Electrocautery, which uses a heated probe to destroy the cyst
- Cryotherapy, in which the gynecologist freezes the cyst with liquid nitrogen
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