Fig. 4.

a Major extranodal extension (ENE), with tumor invading perinodal adipose tissue. The arrow from the capsule to the furthest point of invasion demonstrates how to measure extranodal extension. b Minor extranodal extension with tumor invading adipose tissue with a desmoplastic response. The node capsule is not preserved centrally, nor visualized on the right. An arcuate line has been created to approximate the contour of the node capsule/edge, from which ENE can be measured