Is paget's disease cancerous in all cases?

In Situ or Invasive. Paget's dz represents less than 5% of all breast cancers; cancer cells are found involving the skin of the nipple, resembling eczema.Over 95% of the time an underlying cancer is found elsewhere in the breast, more commonly in-situ rather than invasive. Traditional rx was mastectomy however central lumpectomy (removal of nipple and areola) followed by radiation therapy is an acceptable alternative.