Other Ill-Defined Sites in Lip, Oral Cavity

T-C14 in ICD-O-3 denotes malignant tumors originating in ill-defined or unspecified locations of the lip and oral cavity, used when the precise anatomic subsite cannot be determined. It groups neoplasms that do not fit into more specific lip or oral cavity site codes, serving as a catch-all category for ambiguous oral malignancies.