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SEER Inquiry System - Report
Produced: 11/01/2025 7:11 PM
Question 20130182
Inquiry Details
References:
ICD-O-3
Question:
Primary site--Head and Neck: How is primary site coded if a floor of mouth biopsy reveals microinvasive squamous cell carcinoma but the definitive resection of the tongue and floor of mouth unifocal lesion reveals only in situ squamous cell cancer? See Discussion.
Discussion:
Patient with overlapping lesion of tongue and floor of mouth. Initial biopsy of floor of mouth reveals microinvasive squamous cell cancer. Definitive resection reveals in situ squamous cell cancer. Pathology report states unifocal tumor. The tumor site on pathology report is documented as involving the tongue and floor of mouth.
Should the primary site be coded to floor of mouth because it is the site of invasive disease? Or is primary site C148 [overlapping sites of lip, oral cavity and pharynx] because invasion should not be used to determine primary site?
Answer:
Code the primary site to C068 [overlapping lesion of other and unspecified parts of the mouth]. Based on the information provided, this is a tumor described as a "book-leaf" lesion a lesion that overlaps the floor of the mouth and the underside of the tongue.
Cancer Site Category:
Head & Neck
Data Item Category:
Primary site
Other Category:
N/A
Year:
2013
