Imaging description

Nabothian cysts, named after the German anatomist Martin Naboth who first described them in 1707 [1], are retention or inclusion cysts of the uterine cervix that probably develop when chronic cervicitis results in blockage to the ducts of the mucus-secreting glands of the endocervix [2,3]. At imaging, Nabothian cysts are seen as one or more well-circumscribed unilocular cysts abutting the endocervical canal that are usually a few mm in diameter but occasionally reach 4 cm or more (Figure 82.1) [4, 5]. The term “tunnel cluster” has been applied when multiple small Nabothian cysts are grouped together around the endocervical canal (Figure 82.2) [6], but the value of this term is questionable.

Importance

Incidentally detected Nabothian cysts, particularly at CT (Figure 82.3), may give rise to unjustified concerns of cervical carcinoma, resulting in unnecessary workup and patient anxiety.

Typical clinical scenario

Nabothian cysts are usually easily diagnosed clinically by visual inspection, or are incidental findings at imaging performed for unrelated reasons. Occasionally, extensive cyst formation or large cysts located deeper in the cervix may produce unexplained cervical enlargement and then imaging with ultrasound or MRI may be helpful in further assessment [7].

Differential diagnosis

Solitary Nabothian cysts are distinctive and generally do not carry an imaging differential. When multiple (i.e., tunnel cluster), the primary differential consideration for Nabothian cysts is adenoma malignum, a rare and aggressive mucinous form of cervical cancer that appears as a multicystic mass within the cervix, in contrast to the solid infiltrative appearance of standard non-mucinous cervical cancer.