My Husband Has Had A Rash On His Torso, Front

My husband has had a rash on his torso, front and back, for a year. Been to his GP three times, took steroid shot, creams and allergy meds. Finally sent him to a dermatologist and he immediately thinks it is cutaneous Tcell lymphoma. We are waiting on biopsy, took three, two from back and one from chest. What are the odds that a biopsy can come back false negative. It sounds like many people have numerous biopsies before they come back positive. He will be 63 in May.