11/3- Lab 1: HPV and Pap Smears Flashcards
Cervical cancer is the #__ cause of cancer deaths
Cervical cancer is the #20 cause of cancer deaths
What is the epidemiology of cervical cancer?
- Highest rate of diagnosis in what ages
- Median age at diagnosis
- Highest in what population
- Highest rate of diagnosis in 35-44 yo
- Median age at diagnosis = 49 yo
- Highest incidence in Hispanics
What are the 2 different ways to obtain a cervical vaginal smear?
1. Conventional
- Instrument samples both ecto and endocervix; spread on a slide
2. Liquid based cytology
- Same method, but spatula is placed in liquid fixative and sent to pathology where a monolayer circle slide is produced
- Benefits:
- Machines are used to initially screened slides and this produces uniform, thin sheet
- Allows quick molecular testing for HPV genotypes
What tissue is sampled in pap smear?
- Describe the different types
The transformation zone
- Where the normal columnar mucous-secreting endocervical cells transform into squamous epithelial cells lining ectocervix
- Most cancers arise here
Why is the transformation zone screened so heavily?
It has metaplastic squamous cells predisposed to HPV infection
How does the transformation zone change with age/other health conditions?
The transformation zone is higher in the endocervical canal for young women and those who have not been pregnant
What is seen here?
Normal squamous cells (ectocervix)
- May be “intermediate” or “superficial”
- As the squamous epithelium matures, the nucleus becomes smaller and darker; cytoplasm becomes translucent
- Nucleus of intermediate cell = size gaze for dysplasias
What is seen here?
Normal columnar epithelial (endocervical) cells
What is seen here?
Atrophic smear from post-menopausal (estrogen deficient) woman (could also be seen if breast-feeding or if tumor present)
- Not many mature squamous epithelial cells
- More parabasal cells
Case 1)
- 25 yo woman, G1P0, 12 wks pregnant
- Chief complaint: vaginal itching and thick white “cottage cheese” discharge
- What is the diagnosis?
Candida infection
Describe Candida infection
- Speculum/colposcopic view
- Discharge
- Symptomic infections
- Thick, curd-like discharge
- Symptomatic patients complain of severe pruritus and thick white vaginal discharge
Symptomic infections:
- Diabetes mellitus
- Antibiotics
- Pregnancy
- Immunocompromised states
How does Candida infection appear cytologically?
- Smears may show numerous neutrophils
- Epithelial cell clusters arranged around pseudohyphae in a “Shish kebab” look
- Pseudohyphae of Candida love glycogen that is found abundantly in squamous epithelial cells (why they are so closely associated)
What is seen here?
Candida infection
Case 2)
- 32 yo woman
- Chief complaint: copious yellow discharge
- Exam findings include “strawberry cervix” and abundant yellow discharge
- What is the diagnosis?
Trichomonas infection
Describe a Trichomonas infection
- How common
- Discharge
- Exam findings
- 15% of STD clinics
- Frothy, copious discharge
- Discharge is often malodorous, with a greenish-yellow color
- “Strawberry cervix”: vascular congestion
What causes Trichomonas vaginalis?
- How does it appear on cytology?
- Flagellate protozoan
- T vaginalis are oval or pear shaped and have a small green nucleus and green cytoplasm with red granules
- Flagella is difficult to visualize in PAP smear
How does Trichomonas vaginalis appear cytologically?
- T vaginalis are oval or pear shaped and have a small green nucleus and green cytoplasm with red granules
- Flagella is difficult to visualize in PAP smears
- Smears often show mixed inflammation (lymphocytes and neutrophils)
What is seen here?
Trichomonas vaginalis infection
What is seen here?
Trichomonas vaginalis infection
Case 3)
- 20 yo woman in for routine Pap smear
- Social/GYN history includes menses at 12 years, first intercourse at 16 years; 5 lifetime partners and no tobacco use
- What are some red flags for cervical dysplasia in this history?
- Early age of intercourse (16 yo)
- 5 lifetime partners
How do we make the diagnosis of low grade squamous intraepithelial lesion (LSIL) on a pap smear?
- Compared to nuclei of intermediate cells; LSIL cell nuclei is >3x’s larger
- Moderate variation in nuclear size and shape with occasional binucleation or multinucleation.
- Nuclear hyperchromasia
- The abnormal nucleus is conserved throughout the entire thickness of the squamous epithelium! (CIN I/mild dysplasia)
- Can be picked up just by sampling surface epithelial cells
What else is seen cytologically in low grade dysplasia (apart from nuclear changes)?
Koilocytes (HPV effect): squamous epithelial cells filled with HPV virus particles
- Perinuclear halo
- Nuclear enlargement
- Hyperchromasia and wrinkling
As the virus particles are formed, they destroy the cytoskeleton of the cell, resulting in that wrinkling
- Recall, these are another sign of low grade dysplasia (LSIL)
What is seen here?
LSIL (low grade dysplasia)
What is seen here?
LSIL on colposcopy
- Fine mosaicism (due to irregular vascularity; high grade will have coarser mosaicism)
- Punctuation
What two features can be used to make the diagnosis of low grade dysplasias?
- Mature squamous epithelium with enlarged nucleus (2.5-3x)
- Koilocytes
What are other names/classification systems of mild squamous dysplasia?
LSIL or CIN 1
What are the histological features of mild squamous dysplasia (LSIL) or CIN 1?
- Dysplastic changes involving the lower third of the epithelium.
- The most superficial cells show extensive HPV changes or Koilocytes:
- Perinuclear halo
- Nuclear enlargement, hyperchromasia and wrinkling
Key note on features in dysplasia/the spectrum for mild vs. high grade dysplasia
- Mild dysplasia has abnormal nucleus but mature cytoplasm
- As you progress to higher grade dysplasias, nucleus is still abnormal but now cytoplasm is less mature (less cytoplasm)
Case 4)
- 35 yo woman for follow up Pap smear
- Social/GYN history: menses at 13 yrs, first intercourse at 15 yrs; 7 lifetime partners
- Previous abnormal Pap smears
- Positive for tobacco history
- What’s significant in this history?
Many risk factors for cervical dysplasia
High grade squamous intraepithelial lesions are also called what? What classes are included?
HSIL
- Includes moderate and severe squamous dysplasia/CIS
- CIN 2 and CIN 3 (carcinoma in situ)
(Cytologically, they are just separated mild or high grade dysplasia; this determines management)
What is seen cytologically in high grade squamous intraepithelial lesions?
- Markedly increased nuclear to cytoplasmic ratio (large nucleus and scant cytoplasm), less number of koilocytes
- Sheds in syncytial groups and occasional single cells
- Large hyperchromatic nuclei
What is seen here?
HSIL, high grade dysplasia
- Very abnormal nucleus
- Very little cytoplasm (immature); very high N:C ratios
- Syncytial groups
What is seen here?
HSIL on colposcopy
- Mosaicism (coarser; much more abnormal vasculature than mild)
What is seen histologically in high grade dysplasia?
- CIN 2
- CIN 3
- Dysplastic changes involve up to half of the epithelial thickness (moderate dysplasia or CIN 2)
- Dysplastic changes involve more than half of the epithelium ( Severe dysplasia or CIN 3)
- Dysplastic changes involve the entire thickness of the epithelium (Severe dysplasia /Carcinoma in situ or CIN 3/CIS)
Describe the HPV life cycle
- Virus infects metabolically active cells: metaplastic squamous epithelial cells
- Low grade lesions (LSIL): replicative infections of HPV; virus NOT integrated into host DNA
- High grade lesions (HSIL): viral DNA integrated into host DNA; result in neoplastic cells;
- NOT concerned with replication; therefore, no koilocytes; disrupts function of Rb, p53
What are the HPV types responsible for common warts (most often)?
Types 2 and 5
What are the HPV types responsible for condyloma acuminatum (most often)?
Types 6 and 11
What are the HPV types responsible for laryngeal papillomatosis (most often)?
Types 6 and 11
What are the HPV types responsible for HSIL and squamous cancer (most often)?
Types 16, 18, 31, 33 (also 35, 39, 45, 51)
What are the HPV types responsible for anogenital dysplasia and cancer (most often)?
Type 16
Which type of HPV is the most common cancer causing strain?
Type 16 is the most prevalent high risk viral type
(if you add in 18, you’ve got most of them covered, 70% of cervical cancers worldwide)
