MON-002 Pituitary Predicament: Differentiating Pituitary Abscess From Pituitary Adenoma

Abstract Disclosure: M. Mumpower: None. S. Hall: None. A. Thompson: None. Introduction: Primary pituitary abscess is a rare condition often taking several months to diagnose due to a wide variety of symptoms at presentation and difficulty differentiating from other pituitary lesions. Abscesses and adenomas mimic each other in symptoms including headache, visual disturbance, and endocrine abnormalities. Case: A 32 y/o F with no significant PMH presented to her PCP in 07/2024 due to joint pain and stiffness of 2 months duration. She also noted amenorrhea, galactorrhea, increased urination, and persistent headaches following IUD removal a month prior to presentation. Initial work-up was notable for a low TSH, low T4, and an elevated prolactin level at 167 ng/mL (4.4 - 23.3 ng/mL); thus, she was referred to endocrinology. Repeat workup was significant for an elevated macroprolactin at 138.3 ng/mL (2.8 - 29.2 ng/mL), ACTH stim test with ACTH <1pg/mL (7.2 - 63 pg/mL), and a cortisol level of 10 μg/dL (Before 10am: 3.7 - 19.4, After 5pm: 2.9 - 17.3 μg/dL). Initial MRI head in 08/2024 notable for enhancement along the pituitary gland, concerning for pituitary adenoma or hypophysitis. Patient was unable to tolerate low-dose cabergoline. Repeat MRI in 11/2024 demonstrated an interval increase in size and partial cystic appearance with suprasellar extension of the pituitary gland. The patient was subsequently referred to neurosurgery and underwent a TSR in 12/2024. Intraoperatively, purulent material was expressed from the cystic pituitary mass with cultures growing S. epidermidis and Cutibacterium avidum, for which she completed an extended course of Ceftriaxone and Linezolid. Pathology was consistent with a healing abscess. The patient was treated 3 times for recurrent sinusitis from 05/2024 until TSR. As a result of this pituitary lesion, the patient developed central hypothyroidism, secondary amenorrhea, hypogonadotropic hypogonadism, secondary adrenal insufficiency, and central diabetes insipidus. At follow-up, the patient was recovering well, but hormone function had not returned to baseline. Plans for repeat MRI and labs three months post-op. Conclusion: This case emphasizes the similarities between presentation of pituitary abscess versus adenoma and the differences in management. Ultimately, the management for both pituitary abscess and adenoma is TSR, with abscess requiring tailored antibiotic therapy. Hormone recovery remains poor post-op which highlights the importance of early diagnosis and treatment to help preserve hormonal function. Presentation: Monday, July 14, 2025