Carcinoma In Situ
Also written as: CIS — Carcinoma In Situ
The most severe grade of epithelial dysplasia in which full-thickness cytological and architectural abnormalities are present but the basement membrane remains intact and invasion has not occurred.
Full Definition
Carcinoma in situ (CIS) occupies the extreme end of the oral epithelial dysplasia spectrum and represents a preinvasive state in which malignant cytological features involve the full thickness of the epithelium without breaching the basement membrane. In oral medicine and oral pathology reporting, it is sometimes subsumed under 'severe dysplasia' in grading systems, and editors must be alert to contextual usage. CIS carries a high risk of progression to invasive squamous cell carcinoma and warrants immediate clinical intervention. The hyphenated form 'carcinoma-in-situ' appears in some style guides but the unhyphenated form is standard in most current oncology and oral medicine literature.
Usage
Usage note: Do not hyphenate 'carcinoma in situ' as a noun; hyphenation as a modifier (carcinoma-in-situ lesion) is optional but should be consistent throughout a document.
In Context
- "The biopsy specimen was reported as carcinoma in situ, necessitating urgent referral to the maxillofacial oncology team." — Referral letter
- "Carcinoma in situ is distinguished from invasive squamous cell carcinoma by the integrity of the basement membrane." — Textbook chapter