Pathology Outlines

Cervix
General
Histology

Authors: Kyle Devins, M.D., Lauren Schwartz, M.D.

Editor-in-Chief: Debra Zynger, M.D.

Topic Completed: 19 May 2020

Minor changes: 19 May 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: Cervix[TI] histology[TI]

Page views in 2019: 16,847

Page views in 2020 to date: 6,157

Table of Contents

Cite this page: Devins K, Schwartz L. Histology. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cervixnormalhistology.html. Accessed May 26th, 2020.

Definition / general

Lower portion of the uterus which connects the uterine corpus to the vaginal canal

Essential features

Exocervix is lined by stratified squamous epithelium
Endocervix is lined by columnar mucinous epithelium
Transformation zone is the hormonally responsive zone of metaplasia between the exocervix and endocervix
Squamocolumnar junction is the precise histologic transition between squamous and glandular epithelium
Transformation zone is usual site of persistent infection with high risk subtypes of human papillomavirus (HPV), the most common cause of cervical carcinoma

Physiology

2 anatomic portions:
- Portio vaginalis: anatomic portion of cervix inferior to vaginal reflection and within vaginal canal
- Portio supravaginalis: anatomic portion of cervix superior to vaginal reflection
Ectocervix (exocervix): external mucosal surface of portio vaginalis
- Normally lined by nonkeratinizing stratified squamous epithelium
Endocervix (endocervical canal): mucosa lined cylindrical canal leading from ectocervix to uterine cavity
- Normally lined by single layer of mucinous columnar epithelium
External os: anatomic opening of the endocervical canal onto the ectocervix
- Represents the inferior limit of the endocervix
Internal os: anatomic widening of the endocervical canal as it opens and gradually transitions into the uterine cavity
- Represents the superior limit of the endocervix and distal aspect of the lower uterine segment
Squamocolumnar junction: histologic junction between squamous epithelium of ectocervix and columnar glandular epithelium of endocervix; location changes throughout life in response to hormonal status and age
- Squamocolumnar junction is located on outer surface of portio vaginalis at birth due to effect of maternal hormones; rapidly recedes into endocervical canal until menarche (J Reprod Med 1976;16:221)
- In early adolescence, squamocolumnar junction migrates distally from the external os onto the exocervix in response to pubertal hormones, forming the ectropion
- Ectropion: physiologic ectopic columnar epithelium present on exocervix beginning at adolescence
- Ectropion is gradually replaced by squamous metaplasia throughout reproductive years and the functional squamocolumnar junction slowly recedes towards the external os
- Transformation zone: the physiologic area of metaplastic squamous epithelium between the exocervix and the endocervix; it begins distally at the original squamocolumnar junction present at adolescence and extends proximally to the current functional squamocolumnar junction
- Squamocolumnar junction often recedes within external os following menopause

Diagrams / tables

Contributed by Kyle Devins, M.D.

Schematic of exocervix and transformation zone

Images hosted on other servers:

Location of glandular and squamous epithelium

Clinical features

Transformation zone is the usual site of persistent infection with high risk subtypes of human papillomavirus (HPV), the most common cause of cervical carcinoma (J Clin Pathol 2002;55:244)

Gross description

Cylindrical structure forming lower ~ third of uterus, connecting uterine corpus to vaginal canal
Anatomic position within the pelvic cavity between the urinary bladder (anterior) and rectum (posterior)
Anterior portion can be identified by a higher peritoneal reflection, due to location of the bladder in vivo (J Clin Pathol 1993;46:388)

Gross images

Contributed by Kyle Devins, M.D.

Uterus and cervix

Bivalved uterus and cervix

Microscopic (histologic) description

Ectocervix
- Stratified nonkeratinizing squamous epithelium
  - Basal cells: deepest layer; dense nuclear chromatin, oval nuclei oriented perpendicular to basement membrane, scant cytoplasm
  - Parabasal cells: located just above the basal cell layer; slightly more cytoplasm than basal cells; may be multiple cell layers thick
  - Intermediate cells: abundant cytoplasm which may be pink or clear due to glycogen accumulation
  - Superficial cells: small, round nuclei; abundant pink or clear cytoplasm; cells flatten and are oriented parallel to basement membrane
- Hormone responsive
  - Superficial cells predominate in early cycle due to estrogen
  - Intermediate cells predominate in late cycle due to progestins
  - Loss of intermediate and superficial cells (atrophy) occurs postmenopause
- Rare melanocytes, Langerhans cells and endocrine cells have been identified (Br J Obstet Gynaecol 1983;90:400, Virchows Arch A Pathol Anat Histopathol 1987;411:293)
Endocervix
- Single layer of mucinous columnar cells with dense, oval, basally oriented nuclei and apical mucin
- Variable numbers of ciliated cells
- Inconspicuous underlying reserve cell layer
- Forms infoldings, clefts and glands of variable shape
Transformation zone
- Metaplastic cells: formed by endocervical reserve cells differentiating toward squamous lineage
  - Located at transition between glandular and squamous epithelia
  - Similar appearance to parabasal cells with relatively scant cytoplasm and dense nuclei
- Endocervical glands may underlie squamous epithelium or metaplastic cells
- Variable nonspecific inflammatory infiltrate consisting of lymphocytes, plasma cells and even neutrophils is common and is not necessarily associated with infection
Cervical stroma
- Mostly fibrous tissue with some haphazard smooth muscle fibers
- Blood vessels often numerous and prominent
Mesonephric rests / remnants
- Remnants of involuted embryologic mesonephric (Wolffian) ducts
- Present in lateral cervical wall in ~33% of women
- Microscopic clusters of tubules lined by single layer of cuboidal cells with eosinophilic luminal secretions (Am J Surg Pathol 1990;14:1100)

Microscopic (histologic) images

Contributed by Kyle Devins, M.D.

Squamocolumnar junction

Cervical squamous epithelium

Benign endocervical glands

Dilated endocervical glands

Normal cervical squamous p16 IHC

Normal endocervical p16 IHC

Virtual slides

Images hosted on other servers:

Cervix, normal transformation zone

Cytology description

See cervix - benign features and cervix cytology - preparations

Positive stains

Ectocervix: p63, CK5/6 (Pathology 2007;39:97)
- Ki67 shows low proliferative rate, mostly confined to parabasal cell layer
Endocervix: CK7, PAX8, CEA

Negative stains

p16: negative or patchy (Adv Anat Pathol 2006;13:8)

Additional references

Clin Obstet Gynecol 1983;26:7

Board review style question #1

Which of the following is true about the squamocolumnar junction of the cervix, shown in the image?

Relatively static and does not undergo significant histologic changes after birth
Inflammatory infiltrate at the squamocolumnar junction is abnormal and indicates infection
Migrates distally from the external os during menopause
Migrates distally from the external os in response to estrogens during adolescence

Board review answer #1

D. The squamocolumnar junction and transformation zone are hormonally responsive. The squamocolumnar junction actively migrates distally onto the exocervix in response to estrogens at puberty.

Reference: Cervix - histology (normal)

Comment Here

Board review style question #2

Which of the following best describes the appearance of normal endocervical epithelium?

Columnar cells with basally located nuclei, apical mucin and occasional cilia
Tall pseudostratified nuclei with apoptotic bodies and apical mitotic figures
Stratified cuboidal cells with scattered mucocytes
Stratified nonkeratinizing squamous epithelium

Board review answer #2

A. Normal endocervical epithelium consists of columnar cells with round, basally oriented nuclei and pink apical cytoplasm. Cilia may or may not be present on the apical surface.

Reference: Cervix - histology (normal)

Comment Here