Endocrine Abstracts

Introduction: Lymphocytic hypophysitis (LH) is a heterogeneous inflammatory condition in the pituitary gland, which may cause hormonal deficiency. However, some patients with LH initially present with headache.

Case: A 63-year-old woman complained of a severe headache for 1 month. Examination of cerebrospinal fluid (CSF) showed increased lymphocyte counts, indicating meningitis. Contrast-enhanced magnetic resonance imaging (MRI) revealed an expanding sellar mass with homogeneous enhancement. One month later, MRI showed enlargement of the pituitary mass and formation of a cyst within the mass; however, the patient’s headache had recovered naturally. Seven months later, the patient exhibited loss of appetite and malaise. Cortisol was significantly lowered (ACTH 3.0 pg/ml, cortisol 1.59 μg/dl); therefore, hydrocortisone therapy (15 mg) was initiated. MRI showed a thickening pituitary stalk with a mass, but no cystic lesion in the sellar mass. The patient’s physical condition improved, but she developed polyuria. Water deprivation test confirmed central diabetes insipidus (DI), due to increased urinary excretion (approximately 6 l/day), low specific urinary density (<300 mOsm/l), increased serum sodium (147 mEq/l), increased osmolality (298 mOsm/l), and no change in AVP (0.5 pg/ml). Thus, DI was revealed after steroid therapy, which diagnosed masked DI. Anterior pituitary function was assessed through exogenous administration of releasing hormones and peptide (TRH, CRH, LH-RH, and GHRP); it was disturbed (baseline GH 0.27 ng/ml, stimulated 5.55 ng/ml; IGF1 30 ng/ml; baseline LH <0.10 U/l, stimulated <0.10 U/l; baseline FSH 0.28 U/l, stimulated 0.88 U/l; baseline ACTH <0.20 pg/ml, stimulated 21.7 pg/ml; baseline TSH 0.047 μIU/ml, stimulated 0.237 μIU/ml). MRI indicated shrinkage of the thickened pituitary stalk and accompanying mass. Thus, replacement therapy was initiated: levothyroxine, GH injection, and desmopressin, combined with hydrocortisone. Differential diagnosis included sarcoidosis, IgG4-related disease, and malignant tumors. Chest radiography and examination of IgG4 and angiotensin I-converting enzyme were normal. Changes in the pituitary lesion on MRI were not typical of malignant tumors. Therefore, we diagnosed this patient with LH. In this patient, meningitis preceded LH. However these two diseases might exhibit a casual relationship, CSF findings might be influenced by LH. There is the possibility that meningitis might be a symptom of LH.

Conclusion: We encountered a patient who exhibited LH with disturbance of both anterior and posterior pituitary functions. In this patient, meningitis preceded and might have been a symptom of LH.