7013 An Inpatient Perspective: Hyperprolactinemia and Granulomatous Mastitis

Abstract Disclosure: A. Le: None. J. Wade: None. K. Martz: None. D. Girgis: None. M. Shahlapour: None. M.H. Horani: None. Introduction: Mastitis is a highly prevalent condition impacting thousands of women every year. Most commonly associated with lactation, mastitis is estimated to impact 2-20% of lactating women particularly in the first 4-6 weeks of breastfeeding (Wilson et al., 2020). The majority of cases are associated with bacterial infection with Staphylococcus aureus precipitated by nipple trauma and hyperlactation in the setting of genetic predispositions and disturbances to the human milk microbiota (Fernández et al., 2020). In rare cases, mastitis is seen outside of the context of lactation. One cause of non-lactational mastitis is idiopathic granulomatous mastitis (IGM). The pathogenesis of IGM is poorly understood, but there has been a rare association between IGM and hyperprolactinemia reported in the literature (Nikolaev et al., 2016). Case Presentation: In January 2022, A 20 year old female with past medical history of type 2 diabetes mellitus and hypertension, initially presented to the emergency department with complaints of headache. Patient’s history is notable for two years of amenorrhea and periodic nipple discharge. MRI scan of the head revealed a 1.6 cm pituitary macroadenoma which correlated with a markedly elevated prolactin level at 533.3. She was discharged with a prescription for Cabergoline 0.5 mg BID. In July 2022, the patient presented to the ED complaining of severe left breast pain with associated discharge for 4 days. She admitted to being non-adherent to Cabergoline treatment since April 2022 due to lack of endocrine follow-up. CT of the breast at that time showed a 3.8 cm subareolar abscess. Aspiration of the abscess revealed non-purulent fluid and cultures of the aspirate were negative. In February 2023, patient presented for right breast pain with a similar workup to previous hospitalization. MRI of the brain revealed a 1.6 cm sellar mass is unchanged since January 2022. Prolactin level was elevated at 652.4. Patient stated she has been off Cabergoline for the prior 5 months. She was subsequently seen for right and left mastitis 3 times over the next 12 months. Upon endocrine consultation, the patient was counseled on the importance of Cabergoline treatment in regression of future mastitis episodes, and the patient has subsequently not returned to our service. Conclusion: This case demonstrates the rare association between prolactin secreting pituitary adenomas and granulomatous mastitis that clinicians need to consider in order to avert delays in treatment and unnecessary hospitalizations. Specifically, when working up a patient with a history of IGM and prolactinemia, it is imperative to monitor prolactin levels periodically over an extended course of time with appropriate MRI imaging of the pituitary gland to assess for regression of prolactinoma and episodes of IGM. Presentation: 6/1/2024