Tunnel cluster (TC) is a type of nabothian cyst characterized by complex multicystic dilatation of the endocervical glands.
Tunnel cluster is found in ~8% of adult women, 40% of whom are pregnant, almost exclusively multigravid women, and older than 30 years.
They may occasionally cause mucoid discharge 7.
A tunnel cluster is more likely the result of a stimulatory phenomenon occurring during pregnancy that can persist for a variable period. It is a benign pseudoneoplastic glandular lesion of the cervix and is usually comprised of a rounded aggregate of 20-50 closely packed tubules of varying sizes.
Tunnel clusters can be characterized as:
- type A: non-cystic
- type B: cystic - cystic endocervical tunnel cluster (CETC)
Treatment and prognosis
Tunnel clusters are supposed to be involutional in nature and are usually of no clinical significance 5.
History and etymology
They were first described by Fluhmann in 1961 5.
On imaging appearances consider:
- 1. Bin park S, Lee JH, Lee YH et-al. Multilocular cystic lesions in the uterine cervix: broad spectrum of imaging features and pathologic correlation. AJR Am J Roentgenol. 2010;195 (2): 517-23. doi:10.2214/AJR.09.3619 - Pubmed citation
- 2. Segal GH, Hart WR. Cystic endocervical tunnel clusters. A clinicopathologic study of 29 cases of so-called adenomatous hyperplasia. Am. J. Surg. Pathol. 1990;14 (10): 895-903. - Pubmed citation
- 3. Jones MA, Young RH. Endocervical type A (noncystic) tunnel clusters with cytologic atypia. A report of 14 cases. Am. J. Surg. Pathol. 1996;20 (11): 1312-8. Am. J. Surg. Pathol. (link) - Pubmed citation
- 4. Sugiyama K, Takehara Y. MR findings of pseudoneoplastic lesions in the uterine cervix mimicking adenoma malignum. Br J Radiol. 2007;80 (959): 878-83. doi:10.1259/bjr/16282081 - Pubmed citation
- 5. Jordan JA, Singer A, Jones HW et-al. The cervix. Wiley-Blackwell. (2006) ISBN:1405131373. Read it at Google Books - Find it at Amazon
- 6. Hui P. Cytology and Surgical Pathology of Gynecologic Neoplasms. Springer Verlag. (2010) ISBN:1607611635. Read it at Google Books - Find it at Amazon
- 7. Nucci MR, Oliva E. Gynecologic Pathology. Churchill Livingstone. (2009) ISBN:0443069204. Read it at Google Books - Find it at Amazon
- 8. Okamoto Y, Tanaka YO, Nishida M et-al. MR imaging of the uterine cervix: imaging-pathologic correlation. Radiographics. 2003;23 (2): 425-45. Radiographics (full text) - doi:10.1148/rg.232025065 - Pubmed citation