Intramammary Paget’s disease is an uncommon disease in which 90% of the cases are accompanied by invasive or noninvasive ductal carcinoma. It comprises approximately 0.7%-4.3% of all breast cancers. Typically, extramammary Paget’s disease is accompanied by dermal invasion; however, in intramammary Paget’s disease, dermal invasion through the basement membrane of the skin is very rare. Intramammary Paget’s disease with dermal invasion has been reported infrequently worldwide, and its management and prognosis remain unknown. We report a case of intramammary Paget’s disease with dermal invasion in a 64-year-old woman, accompanied by review of the literature.