MON-110 Coexistence Of Primary Adrenal Insufficiency And Pituitary Macroadenoma: A Rare Endocrine Intersection

Abstract Disclosure: N. Tedoradze: None. M. Pailodze: None. Z. Malazonia: None. V. Tsikarishvili: None. Background: Pituitary macroadenomas frequently cause hormonal deficiencies due to mass effect and compression of the surrounding pituitary tissue. Central adrenal insufficiency is a common consequence of such lesions. In contrast, primary adrenal insufficiency is rarely reported in association with pituitary tumors. Nevertheless, a few case reports suggest, the chronic absence of cortisol-mediated negative feedback may contribute to pituitary hyperplasia or adenomatous transformation. The coexistence of primary adrenal insufficiency and a pituitary macroadenoma poses diagnostic and therapeutic challenges and raises questions regarding possible pathophysiological interactions. Case Presentation: We describe the case of a 52-year-old female with a three-year history of progressive constitutional symptoms, including persistent fatigue, episodic morning headaches, emotional lability, and blood pressure fluctuations characterized by alternating hypo- and hypertensive episodes. The patient also reported long-standing secondary amenorrhea since age 35 and progressive visual disturbances consistent with bitemporal hemianopsia. Brain MRI demonstrated a large pituitary macroadenoma measuring 4.1 × 4.2 × 4.3 cm, with suprasellar extension compressing the optic chiasm, bilateral parasellar invasion, hypothalamic compression, and deviation of the pituitary stalk. Laboratory evaluation revealed a complex hormonal profile: central hypothyroidism, mild hyperprolactinemia, and primary adrenal insufficiency characterized by markedly elevated plasma ACTH levels with undetectable serum cortisol. Initial management included stress-dose corticosteroid replacement with hydrocortisone acetate and levothyroxine sodium for thyroid hormone replacement. Following stabilization, the patient underwent successful endoscopic transsphenoidal resection of the tumor.Postoperatively, she developed diabetes insipidus, managed effectively with desmopressin. Subsequent hormonal reassessment showed normalization of prolactin levels, improvement in central thyroid function, and a decline in ACTH concentrations, although still within the high-normal range. Mineralocorticoid replacement with fludrocortisone was not initiated due to consistently normal serum electrolytes and stable blood pressure. Conclusion: This case underscores the rare but clinically significant coexistence of primary adrenal insufficiency and a pituitary macroadenoma. The presence of primary adrenal insufficiency in a patient with a pituitary tumor complicates the differentiation between primary and secondary causes of hormonal dysfunction. Individualized hormonal replacement and a multidisciplinary approach are critical for optimizing clinical outcomes in such complex endocrine disorders Presentation: Monday, July 14, 2025