Hi,Welcome with your query to HCM virtual Clinic.
I reviewed all the details of your query,in context of the of the large lump on your husband's back.
Based on the facts of your query,You seem to have infected Sebaceous
Cyst,which though firm/soar and existing there for 4 yrs without any increase in size,has been confirmed by your doctor as not emergency problem as off now.
This ambiguity in the diagnosis by your doctor,indicates confusion in its assessment and to resolve this I would suggest
Second Opinion from ER Surgeon,who would confirm its cause and diagnosis by physical examination and by USG if need be and would treat it in the best possible way.
So you need to have Second Opinion from Er Surgeon.
Hope this reply would help you to plan treatment with your doctors and resolve your worries.
Will appreciate writing excellent review comments to help the needy patient visitors like you at HCM.
Welcome any further query and information in this regard.
Good Day!!
Dr.Savaskar M.N.
M.S.Genl-CVTS