Prolactinoma: These common adenomas secrete excessive prolactin and generally have different presentations in women and men. The normal prolactin level is generally less than 20 ng/ml. In most women with prolactinomas, the tumors are detected when they are smaller (microadenomas) and the prolactin level is only moderately elevated (50 - 300 ng/ml). In contrast, in men prolactinomas are often detected when they larger (macroadenomas) and often have prolactin levels over 500 - 1000 ng/ml. Learn more.