Abstract #1398468: Lymphocytic Hypophysitis Successfully Treated with Prednisone

Abstract

Lymphocytic Hypophysitis is an inflammatory disorder of the pituitary gland that has classically been described in pregnant and postpartum women. It is the most common type of Primary Hypophysitis which refers to inflammation of the pituitary gland that is not secondary to other systemic diseases or drugs. This is a rare group of disorders with an estimated annual incidence of 2.4 in 10 million. We present the case of a young woman diagnosed with Lymphocytic Hypophysitis and successfully treated with prednisone. A 27-year-old previously healthy female presented with daily headaches and fatigue that began 4 months after an uncomplicated vaginal delivery. She was amenorrheic despite cessation of breast milk production. Physical exam was within normal limits. Laboratory evaluation revealed an AM cortisol of 1 mg/dl (4-22), Free T4 of 0.4 ng/dL (0.8-1.8), LH of 0.5 mIU/mL (1.9-12.5), and estrogen of 30 pg/ml (12.5-166, follicular), consistent with adrenal insufficiency, hypothyroidism, and hypogonadism. Prolactin was normal. She had no evidence of Diabetes Insipidus. MRI pituitary with and without contrast revealed an intensely and homogenously enhancing sellar mass measuring 2 x 2 x 1.3 cm with suprasellar extension and mass effect on the optic chiasm. She did not have any abnormalities in her visual fields or acuity. Lymphocytic Hypophysitis was felt to be the most likely diagnosis based on her clinical presentation and imaging features. Via shared decision-making, she was started on 40 mg of oral prednisone daily in addition to levothyroxine and oral combined contraceptive pills. On reevaluation 2 months later, her symptoms improved and a repeat MRI revealed a dramatic improvement in the appearance of the lesion following which prednisone was reduced to 30 mg with a plan for revaluation after 2 more months. Lymphocytic Hypophysitis should always be suspected in pregnant and postpartum women with neurological complaints of headaches or visual abnormalities and pituitary hormonal deficiency. The investigation involves obtaining an anterior pituitary hormonal profile including TSH with free T4, ACTH with cortisol, FSH, LH, estradiol, and prolactin. Serum sodium with plasma and urine osmolality can be used to evaluate diabetes insipidus in suspected cases. MRI pituitary with and without contrast frequently reveals a symmetric sellar lesion that enhances intensely and homogeneously with gadolinium. A pituitary adenoma, in contrast, enhances less than the normal pituitary tissue. A tool based on clinical and radiological features called the Gutenberg score can also aid in differentiating lymphocytic hypophysitis from an adenoma. Treatment involves management of hormonal deficiencies including Diabetes Insipidus and relief of symptoms of mass effect. Glucocorticoids can induce remission and possible recovery of hormonal function. Follow-up with serial imaging in a few months after initiation of glucocorticoids is essential. Diagnosis needs to be reconsidered if there is no improvement in the appearance of the lesion and a pituitary biopsy may be indicated.