Squamous cell carcinoma

Microinvasive squamous cell carcinoma

Topic Completed: 1 June 2016

Minor changes: 30 November 2020

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PubMed Search: Microinvasive squamous cell carcinoma cervix

Ashwyna Sunassee, M.D.
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Cite this page: Sunassee A. Microinvasive squamous cell carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cervixmicroinvasivescc.html. Accessed December 3rd, 2021.
Definition / general
  • Invasive squamous cell carcinoma diagnosed by microscopy only (TIa)
  • Invasion is limited to measured stromal invasion with a maximum depth of 5 mm and no wider than 7 mm diameter
  • TIa1: Stromal invasion ≤ 3.0 mm in depth and horizontal spread ≤ 7.0 mm
  • TIa2: Stromal invasion > 3.0 mm but not more than 5.0 mm in depth and horizontal spread ≤ 7.0 mm (J Obstet Gynaecol 2010;30:433)
Essential features
  • Invasive squamous cell carcinoma diagnosed by microscopy only (not seen grossly)
  • Associated with high risk HPV (Glowm)
  • Lymphovascular invasion is an important prognostic factor
  • Young women in childbearing age, which coincides with the most common period for the onset of preneoplastic cervical lesions (Cancer 2010;116:2343)
Prognostic factors
  • Lymphovascular invasion
  • Depth of invasion
  • Endocervical margin involvement (endocervical curettage positive) after LEEP associated with significantly increased risk of recurrent/residual disease (J Obstet Gynaecol Res 2016;42:457)
Case reports
  • Coexisting microinvasive squamous and adenocarcinoma of the cervix (Onco Targets Ther 2016;9:539)
  • Multifocal microinvasive squamous cell carcinoma with extensive spread of squamous cell carcinoma in situ into the uterine corpus, vagina and left salpinx diagnosed five years after conization of cervical CIS (Eur J Gynaecol Oncol 2014;35:600)
  • Stage Ia1
    • Simple hysterectomy
    • LEEP and conization if fertility preservation desired
  • Stage Ia2
Gross description
  • Often abnormal vessels at colposcopy – mosaic and punctate
Microscopic (histologic) description
  • Irregularly shaped tongues of epithelium projecting into stroma
  • Invasive cells exhibit individual cell keratinization, loss of polarity, pleomorphism, cellular differentiation, prominent nucleoli, desmoplastic stroma
  • Breach of basement membrane by reticulin stains (also type IV collagen or laminin)
  • Vascular involvement may be present (increased involvement with depth of tumor invasion)
Microscopic (histologic) images

AFIP images

Irregularly shaped
tongues of squamous

Differentiated overlying
squamous epithelium

Small invasive buds

Individual cell keratinization of invasive cells

Suggestive of angiolymphatic invasion

Measuring depth of invasion

Angiolymphatic invasion
confirmed by factor VIII
related antigen immunostain

HSIL with focal necrosis
and nearby angiolymphatic

Images hosted on other servers:
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Measuring depth of invasion

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Various images

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Small invasive buds

Cytology description
  • Microinvasive cancer is a histologic diagnosis and depends on the extent of stromal invasion
  • The diagnosis of microinvasive cancer cannot be made cytologically because of the inability of cytologists to judge the extent of stromal invasion simply by looking at cellular characteristics alone
  • Findings include cellular and nuclear pleomorphism, disorganized cellular polarity, presence of nucleoli, and keratinization (Glowm)
Positive stains
Differential diagnosis
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