What is a nabothian cyst and how is it treated?

Nabothian Cysts: Definition and Treatment

Nabothian cysts are benign mucous retention cysts of the cervix that typically require no treatment unless they become symptomatic or unusually large.

Definition and Pathophysiology

Nabothian cysts are common benign cervical lesions that form when cervical glands become blocked, leading to the accumulation of mucus inside these blocked cervical crypts 1, 2. They are:

• Non-neoplastic mucinous cystic lesions of the uterine cervix
• Most common in women of reproductive age
• Often develop following childbirth, minor trauma, or inflammation that causes blockage of cervical glands

Clinical Presentation

Most nabothian cysts are:

• Small (typically less than 4 cm)
• Asymptomatic
• Incidental findings during routine pelvic examination

However, in rare cases, they can:

• Grow to significant sizes (reports of cysts up to 15 cm have been documented) 3
• Present with symptoms such as:
  • Pelvic pain or pressure
  • Dyspareunia (painful intercourse)
  • Abnormal uterine bleeding
  • In extreme cases, they may even contribute to uterine prolapse 1 or obstruct labor passage 4

Diagnosis

Diagnosis is typically made through:

1. Physical examination: Visual inspection of the cervix often reveals smooth, round elevations on the cervical surface

2. Ultrasound imaging: First-line imaging modality

   • Simple nabothian cysts appear as anechoic (fluid-filled), well-circumscribed lesions with thin walls and posterior enhancement 5, 6
   • May be classified as:
     • Simple cysts (anechoic with well-defined walls)
     • Complicated cysts (contain low-level echoes without solid components)
     • Complex cysts (have solid components or thick walls)

3. MRI: Used for larger or atypical cysts to differentiate from malignancy

   • Nabothian cysts typically appear as round or oval cysts without enhancement after gadolinium administration 7
   • Helpful to distinguish from minimal-deviation adenocarcinoma (MDA)

Treatment

The management of nabothian cysts depends on their size, symptoms, and characteristics:

1. Asymptomatic small cysts (most common scenario):

   • No treatment required 6
   • Return to routine screening
   • These are considered normal physiologic findings

2. Symptomatic simple cysts:

   • Therapeutic aspiration may be performed for symptom relief 5
   • If the fluid is bloody, cytologic examination is recommended 5

3. Large or complex cysts:

   • Biopsy or excision may be warranted to rule out malignancy, especially for:
     • Cysts larger than 4 cm
     • Cysts with complex features on imaging
     • Cysts with solid components
   • This is particularly important as large nabothian cysts can mimic malignancies such as adenoma malignum 2, 3

4. Surgical options for large symptomatic cysts:

   • Excision (can be performed laparoscopically in many cases) 2
   • In perimenopausal or postmenopausal women with other gynecologic issues, hysterectomy may be considered if other indications exist 3

Follow-up

• For simple, asymptomatic nabothian cysts: routine gynecologic screening
• For complicated cysts that are not excised: follow-up with physical examination and ultrasound every 6-12 months for 1-2 years to assess stability 5
• Biopsy is recommended if the cyst increases in size during follow-up 5, 6

Important Considerations

• While most nabothian cysts are benign, large or complex cysts should be evaluated to rule out malignancy
• The risk of malignancy in simple cysts is extremely low, but complex cysts have a higher risk (14-23%) 6
• Unusual presentations of nabothian cysts (very large size, rapid growth, complex features) warrant further investigation
• Careful preoperative examination with appropriate imaging is crucial to avoid unnecessary invasive procedures 2

Remember that while most nabothian cysts are benign and require no intervention, proper evaluation is essential to distinguish them from more concerning pathologies, particularly in cases of large or atypical cysts.