Extranodal extension (ENE) is defined as "the extension of a nodal metastasis through the lymph node capsule into adjacent tissue" and is a prognostic factor for most head and neck tumors. This data item pertains to pathological staging extension.

Extranodal Extension Head and Neck Pathological is a Registry Data Collection Variable in AJCC. It was previously collected as Head and Neck SSF# 9 (Common SSF).

Item #	Length	Source of Standard	Year Implemented	Version Implemented	Year Retired	Version Retired
3832	3	NAACCR	2018	18

0.0	Lymph nodes positive for cancer but ENE not identified or negative
0.1-9.9	ENE 0.1 to 9.9 mm
X.1	ENE 10 mm or greater
X.2	ENE microscopic, size unknown Stated as ENE (mi)
X.3	ENE major, size unknown Stated as ENE (ma)
X.4	ENE present, microscopic or major unknown, size unknown
X.7	Surgically resected regional lymph nodes negative for cancer (pN0)
X.8	Not applicable: Information not collected for this case (If this information is required by your standard setter, use of code X.8 may result in an edit error)
X.9	Not documented in medical record No surgical resection of regional lymph nodes ENE not assessed pathologically, or unknown if assessed Pathological assessment of lymph nodes not done, or unknown if done

Each Site-Specific Data Item (SSDI) applies only to selected primary sites, histologies, and years of diagnosis. Depending on applicability and standard-setter requirements, SSDIs may be left blank.