Should I be worried about a big lump on my breast and an itchy nipple (not on the areola) with throbbing pain that comes and goes?

There is no evidence of protopic cream causing breast cancer. However there are cases of the cream resulting in skin cancer and lymphoma. A dermatologist or an oncologist will be more suited to explain further on this.

Hi there, Your symptoms sound like they way be related to some form of nipple eczema or dermatitis. Especially since the symptoms worsen with sweating and is associated with intense itch. What you should do is to see a doctor for a consultation as only when a doctor examines the area of concern can we form a better clinical diagnosis and help you treat your condition better. Hope this helps.