SAT589 A Case Of Lymphocytic Hypophysitis In A Young Female With Unilateral Abducens Nerve Palsy

Abstract

Abstract Disclosure: J.H. Yu: None. M.L. Nguyen: None. M.H. Horani: None. M. Shahlapour: None. Lymphocytic hypophysitis is a neuroendocrine disorder characterized by autoimmune inflammation of the pituitary gland. Lymphocytic hypophysitis is the most common form of hypophysitis with the cause usually unknown. It often occurs in late pregnancy or in the postpartum period with affected individuals presenting with symptoms of headaches of an intensity out of proportion to the size of the lesion and with hypopituitarism. Other manifestations include visual field defects and ocular motility disturbances. We present a case of a 24 year old Female who presents with headache, diplopia, and left-sided CN6 nerve palsy of 4 day duration. She has a known history of amenorrhea for the past year and obesity. She also presents with polydipsia and polyuria. Further workup included MRI of the brain showing a sellar mass with mass effect on optic chiasm and left cavernous sinus lesion. Pituitary hormonal workup showed ACTH 13, LH 0.42, FSH 2.1, TSH 0.442, free T4 1.0, random cortisol 6.3, and prolactin 78. Lumbar puncture with basic CSF studies showed glucose 56, protein 48, nucleated cells 38 (lymph 91%, poly 4%, mono 5%), and RBC 4. ACE, AFP, IgG4, ANA, ANCA, and CEA workup was negative. Biopsy of the mass was performed with results suggesting lymphocytic hypophysitis. Additional immunohistochemistry stains will be performed to evaluate for IgG4 related diseases. The patient would later develop diabetes insipidus and central hypothyroidism weeks later. Discussion: The lymphocytic infiltration causes inflammation, enlargement and fibrosis of the pituitary gland which can produce a mass effect on surrounding tissues. The definitive diagnosis is made via histopathology staining of biopsied sellar or suprasellar tissue. The condition predominantly affects women more than men at a ratio of 8:1.Treatment involves evaluation of pituitary function with management of any hormone deficiencies and alleviating any mass effects due to pituitary inflammation and enlargement. First line treatment usually involves high dose corticosteroids with refractory cases being treated with immunosuppressive medications. Surgery or fractionated radiotherapy can be used if medical therapy fails. In our patient, a biopsy was performed that confirmed lymphocytic hypophysitis with unmasked diabetes insipidus and hypothyroidism presenting weeks after starting on high-dose corticosteroids. Conclusion: This case highlights the unique presentation of lymphocytic hypophysitis including left-sided CN6 nerve palsy, headaches, and hypogonadotropic hypopituitarism. From our knowledge, it is one of the first presentations with unilateral CN6 nerve palsy as a mass effect from lymphocytic hypophysitis. Presentation: Saturday, June 17, 2023