Endocrine Abstracts

Introduction

Lymphocytic hypophysitis is an autoimmune inflammatory pathology of the pituitary gland responsible for partial or global hypopituitarism. In this context, we report a clinical case illustrating this entity.

Clinical case

A 31-year-old woman with a family history of hypothyroidism and a personal history of vitiligo was seen in the 8th month of pregnancy for headaches that have progressed rapidly in 4 weeks. She reported visual blurring, without asthenia nor polyuropolydipsic syndrome. Ophthalmologic examination showed normal fundus and bitemporal amputation of the visual field. The hormonal balance showed a thyrotropic insufficiency with a low TSH at 0.25 mui/l and a low ft4 at 10.2 pmol/l, an intact corticotropic axis, and normal baseline GH and IGF1 levels. The pituitary MRI showed symmetrical pituitary hypertrophy heterogeneous and hypersignal in T2 ponderation, and isosignal in T1, compressing the optic chiasma, the posterior pituitary lobe was in place with spontaneous hypersignal in T1 ponderation. Therapeutically, the patient received oral corticosteroid therapy at a dose of 0.5 mg/kg/day over a period of one month in the peri-partum followed by gradual decline over one month. The evolution was marked by the regression of the headaches. A cesarean delivery was decided because of the risk of intracranial hypertension. Pituitary imaging was practiced two months after childbirth, showing a marked decrease in pituitary volume at the expense of the suprasellar region with relief of compression on the optic chiasma. The patient underwent a hormonal reassessment thus eliminating iatrogenic corticotropic insufficiency after stopping corticosteroid therapy. She was treated with L-thyroxine replacement therapy in front of a deficient thyreotropic axis. Four months later the patient developed weight loss with orthostatic hypotension. Pituitary assessment showed corticotropic insufficiency and control imaging showed a decrease in pituitary size with an upper edge concave upwards. She was then put on hydrocortisone at a dose of 15 mg per day with a good clinical outcome.

Conclusion

Lymphocytic hypophysitis is a rare entity whose best known mechanism is an immune disorder. The presence of a history of autoimmune diseases, the female sex and the pregnant state are strongly suggestive of this etiology. The median and symmetrical nature of the pituitary hypertrophy on imaging is also ecovative of this diagnosis. This is an evolving pathology, so the deficit of the pituitary axes may appear later, hence the benefit of a regular clinical and biological monitoring of the pituitary axis.