Association between Hyperprolactinemia and Granulomatous Mastitis

Granulomatous mastitis ( GM ) is a relatively uncommon inflammatory breast lesion with multiple suggested etiologies. Although most GM cases show association with lactation and pregnancy, a minority of cases have been linked to hyperprolactinemia caused by either dopamine antagonist medications or with intracranial lesions, such as pituitary adenoma. The goal of this study is to review the GM cases reported in the literature with a specific emphasis on those cases associated with hyperprolactinemia and prolactinomas and to identify cases of GM seen at the Cleveland Clinic Florida which demonstrate co‐occurrences of GM and intracranial lesions. CoPath and Epic data bases at Cleveland Clinic Florida were searched for cases describing inflammatory breast lesions in patients with pituitary pathology. Chart reviews were conducted and pertinent medical history was extracted for case reports. H&E‐stained paraffin‐embedded sections retrieved from Cleveland Clinic Florida pathology storage were evaluated by light microscopy. Four cases showing a co‐occurrence of GM and hyperprolactinemia were consequently identified. A prolactin‐secreting pituitary adenoma was present in two of the three GM cases. The third case demonstrated a concomitant craniopharyngioma, which was also associated with a rise in serum prolactin. This phenomenon was presumably attributable to compression, resulting in compromised transport of dopamine to the adenohypophysis and subsequent disinhibition of prolactin secretion by lactotrophs. The fourth patient with GM had a similar history of elevated prolactin. Classical histopathological features of GM were found in all four cases, including noncaseating granulomas, multinucleated giant cells, epithelioid histiocytes, and chronic inflammation. Intriguingly, complete resolution of inflammatory breast lesions along with normalization of prolactin levels occurred following the surgical excision of the craniopharyngioma, suggesting that intracranial lesion–induced hyperprolactinemia might be directly causal in GM . Therefore, the authors would suggest screening for pituitary tumors and evaluate prolactin levels in the workup of GM patients without a recent history of lactation and pregnancy and no other identified etiology.