Abstract Disclosure: M. Siddiqui: None. U. Rafat: None. S. Shaik: None. J.L. Gilden: None. Background: The Pineal Gland receives information through a complex multi-neuronal pathway and is responsible for the secretion of melatonin, a hormone regulated by circadian rhythm and suppressed by light stimuli. Melatonin is involved in biological rhythms and regulates immunomodulation, temperature homeostasis and maturation of hypothalamic-pituitary and gonadal axis, and can also modulate thyroid, prolactin, growth hormone, cortisol, and ACTH activity. Other effects include downregulation of thyroid activity. In addition, studies have shown that pineal body extracts can cause a minor increase in the zona glomerulosa and fasciculata of the adrenal gland. Case: A 54-year-old male with recurrent nephrolithiasis, obstructive sleep apnea and chronic rhinosinusitis, first presented to Endocrinology Clinic in 2018 for evaluation of an incidental adrenal adenoma (CT abdomen -2.8 cm, less than 10 Hounsfield units, left sided lipid rich adrenal adenoma). He had new onset erectile dysfunction, decreased libido, and fatigue. Initial lab work including LH, FSH, TSH, midnight salivary cortisol, ACTH, plasma cortisol AM, free and total testosterone, aldosterone, plasma and urine metanephrines/normetanephrines were all normal. MRI brain-1 cm thin-walled pineal cyst with internal characteristics compatible with proteinaceous benign pineal cyst. He was then lost to follow-up for 5 yrs due to the COVID pandemic. He had tried taking “testosterone protein builders”, but his symptoms remained. In addition, he now has twice weekly dull occipital headaches, relieved by ibuprofen. Lab tests-elevation in 1of 2 MN salivary cortisol samples at 0.58 mcg/dL (nl≤0.09), ACTH 12pg/mL(0-47), IGF1 261 ng/mL(50-317), and low total testosterone 222 ng/dl (250-1100) Free testosterone 36 pg/mL(35-155), borderline low TSH 0.386 µIU/ml(0.55-4.78), Free T3 and Free T4 were normal, thyroid antibodies-negative . Rest of the hormone evaluation was otherwise normal, LH 4.90 mIU/mL(1.5-9.3), FSH 11.10 mIU/mL (1.4-18.1), Prolactin 6.8 ng/mL(2.1-17.7). Thyroid Ultrasound-homogeneous echogenicity of the thyroid gland without discrete thyroid nodules. Repeat MRI brain- benign pineal cyst which was stable with no midline shift or mass effect. Repeat CT adrenal gland-lipid rich adrenal adenoma slightly reduced in size from 2.8 to 2.4 cm. Lab tests returned to normal one month later. Conclusion: Although it is unclear whether there is an exact association between this patient’s pineal cyst and adrenal adenoma, there have been intermittent hormonal abnormalities and symptoms consistent with hypogonadism and/or adrenal, also possibly related to the pineal abnormality. Although more research needs to be conducted explaining the relationship between the pineal and pituitary, and the adrenal gland, this clinical case suggests that there may be a relationship between these two abnormalities and symptoms. Presentation: 6/2/2024