SAT-243 Lymphocytic Hypophysitis Mimicking Pituitary Apoplexy in a 27-Year-Old Woman

Introduction: Lymphocytic hypophysitis is an uncommon inflammatory disorder of the pituitary gland. Peripartum women are most often affected, but it can be seen in a wide range of patients. Patients can present with pituitary dysfunction or mass effect symptoms, making it difficult to differentiate from a pituitary adenoma. Pituitary apoplexy is an acute syndrome due to hemorrhage into the pituitary gland causing headache, visual deficits, and hypoadrenalism. We present a case of a woman with a pituitary mass presenting with symptoms mimicking pituitary apoplexy, in whom surgical pathology later revealed lymphocytic hypophysitis without evidence of hemorrhage. Clinical Case: A 27-year-old non-pregnant female presented with severe headaches, nausea, vomiting, and diplopia for four days. A presumed pituitary macroadenoma was diagnosed two years previously during a workup for irregular menses. An emergency evaluation with a CT angiogram of the head showed enhancement at the superior aspect of and surrounding the pituitary gland. MRI of the pituitary revealed an enhancing 17 x 17 mm sellar and suprasellar mass compressing the optic chiasm, without evidence of the normal pituitary posterior bright spot. Visual field testing was normal. She was referred for transsphenoidal resection of the pituitary mass due to persistent headaches, optic chiasm impingement, and suspicion of pituitary apoplexy. Intraoperatively, there was no evidence of hemorrhage. Central diabetes insipidus and hypothyroidism developed in the post-operative period. She was discharged on hydrocortisone replacement therapy (20 mg in the morning, 10 mg in the afternoon). An outpatient random cortisol level of 1.2 mcg/dL (reference: 6.7 - 22.6 mcg/dL) while off hydrocortisone for twenty-four hours confirmed hypocortisolism. Surgical pathology showed moderate lymphocytic infiltrate and focal germinal centers in the adenohypophysis consistent with lymphocytic hypophysitis. Conclusion: Although lymphocytic hypophysitis is well-described in the literature, its association with symptoms suggesting pituitary apoplexy has been reported only rarely. This atypical case shows that lymphocytic hypophysitis can present with acute symptoms mimicking pituitary apoplexy. The case highlights the difficulties in recognizing lymphocytic hypophysitis prior to surgery and emphasizes the need to consider the diagnosis in patients presenting with pituitary masses and/or symptoms of pituitary apoplexy.