Hi Amy,
My understanding of extracapsular spread is that there are cancer cells outside the original tumor. When I've tried to research this on the web, almost invariably, extracapsular and lymph node involvement are used in the same sentence.

Not being a doctor, I can't shed much light on this but I suppose that cancer cells that have moved outside the original tumor and invaded nearby muscle tissue, for example, would be considered extracapsular but not involving the lymph nodes.

Maybe someone more knowledgeable on the forum can help. Best, Sheldon