PMON75 Unilateral Galactorrhea in an Elderly Male

INTRODUCTION/BACKGROUND: Galactorrhea in men is rare, with a reported prevalence of 5.5%. It tends to occur bilaterally rather than unilaterally. Among the etiologies of galactorrhea, pharmacologic agents, pituitary tumors, and hypothalamic and pituitary-stalk lesions tend to account for most cases. Here we describe a rare cause of unilateral galactorrhea due to previous herpes zoster in the T4 dermatome. CLINICAL CASE: A 76-year-old male with history of hypertension, Crohn's disease, and chronic migraine headaches presented to the Endocrine clinic for evaluation of intermittent unilateral galactorrhea, which had been ongoing for the past 5 years. The patient had no known precipitating events, but he had noticed that galactorrhea was more pronounced in the spring-summer seasons, during which time he used to work outdoors more. No history of cancer, hypothalamic-pituitary disease, or other endocrinopathies. The patient was a former smoker and denied marijuana or alcohol use. He reported a family history of breast cancer in his maternal grandmother. He had no biological children. Active medications included sumatriptan as needed for migraines. Physical examination was notable for gynecomastia that was more prominent on the left. Tenderness to palpation was noticed over the left breast with no exudate expressed from the nipples. Genital exam revealed decreased testicular volume at approximately 10 ml each. Laboratory evaluation revealed normal renal function, prolactin, estradiol, β-HCG, TSH, and normal male karyotype. Testosterone level was low with elevated LH and FSH, suggesting primary hypogonadism. Mammogram and US of the breast were not concerning for malignancy. MRI brain was without pituitary abnormalities. After a detailed discussion on a subsequent follow-up visit, the patient recalled an episode of herpes zoster infection over his left breast about 5 years ago and since had been experiencing left breast pain and nipple discharge. DISCUSSION AND CONCLUSION: We present a unique case of post-herpetic galactorrhea in an elderly male patient. In the literature, there are case reports that describe galactorrhea in patients post chest wall injuries or chest surgeries, and there was one case report of galactorrhea in a postmenopausal female post zoster infection. A possible mechanism of galactorrhea is thought to be stimulation of the lactational neural arch, and in our case, possibly stimulated by the zoster infection. Prior herpes zoster infection and post-herpetic neuralgia are likely causes for underlying intermittent unilateral galactorrhea. Albeit rare, clinicians should be aware of this etiology when comprehensively evaluating for galactorrhea. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.