Relationship between serum prolactin levels and histology of benign and malignant breast lesions: a detailed study of 153 consecutive cases.

This study was aimed at investigating the relationship between serum prolactin levels and the morphology of operable female breast lesions. One hundred fifty-three consecutive patients with operable benign and malignant breast lesions in whom preoperative serum prolactin levels had been determined were stratified into five groups according to their serum prolactin levels. The histologic findings in these groups were analyzed and compared. Most patients (93%) had serum prolactin levels within the normal limits. Of the 54 patients with benign lesions, only 4(7%) had slightly elevated serum prolactin levels. Two of these patients had fibroadenomas, one had a phyllodes tumor and one had fibrocystic change. Of the 99 patients with carcinoma, 7 (7%) had hyperprolactinemia. Five of the seven tumors were invasive and two were in situ. All seven tumors were of low or intermediate grade of malignancy. The two cases with the highest prolactin levels (3057 and 1822 mU/L) were both intermediate-grade ductal carcinoma in situ (DCIS). It is concluded that the great majority of patients presenting with operable breast lesions have normal serum prolactin levels, and that elevated levels, when present, occur with equal frequency in patients with benign and malignant breast lesions. Hyperprolactinemic patients presenting with carcinoma in this study, none of whom had a history of recent pregnancy or lactation, tended to have histologically low- or intermediate-grade tumors, but this needs to be confirmed by investigating more cases.