Endocervical tunnel clusters
- Well-demarcated lobulated closely packed variable size cystically dilated glands, just below the surface endocervical mucosa
- Glands are lined by a flattened epithelium with bland nuclear features and basally located nuclei.
- Cystically dilated glands contain thick mucinous secretion
- Here, the overall low-power look resembles that of colloid goiter.
- Few large Nabothian cysts are also seen
- Glands do not have cytologic atypia, mitoses, and infiltrative look with a desmoplastic stromal response.
Practical points of Pathoclinics:
- It is a benign condition of endocervical glands,
- There are usually asymptomatic and common incidental findings during routine cervix biopsy processing, especially in postmenopausal and pregnant women.
- Grossly endocervical tunnel clusters are not visible.
- The typical location is close to the surface epithelium of the cervix.
- Two types of tunnel clusters (1) small size non-cystic, closely packed glands lined cuboidal or columnar/mucinous epithelium and (2) Large size cystic glands lined by a single attenuated layer of cuboidal cells with basally located nuclei.
- There are no cytologic atypia, no stromal reaction, and no mitoses in both types. Glands are clustered with a smooth margin, giving lobulated appearance. Importantly, glands do not infiltrate the deep stroma, so endocervical tunnel clusters should not be misinterpreted as minimal deviation adenocarcinomas. Later has irregularly infiltrative glands in a desmoplastic stroma. Tunnel clusters are uniformly positive for ER and PR. PAX2 is positive in endocervical tunnel clusters. Minimal deviation adenocarcinomas are negative