Nonpuerperal mastitis (NPM) is characterized by chronic nonspecific inflammation, complex pathological types, and unclear causes. Prolactin seems to play an important role in the occurrence and development of NPM. This study reports two cases of mastitis with prolactinoma. While treating mastitis, active treatment of prolactinoma and reduction of prolactin levels have achieved good curative effects. Keywords: non-puerperal mastitis; prolactinoma; hyperprolactinemia.