Endocrine Abstracts

Introduction

Hypopituitarism is a rare condition defined by loss of pituitary function due to involvement of hypothalamus and/or pituitary gland by infiltrative diseases mainly sarcoidosis and Langerhans cell histiocytosis (LCH). Central diabetes insipidus is the most frequent manifestation of LCH (10–50%) and rarely in neuro-sarcoidois. Herein, we describe 2cases of hypopituitarism due to neuro-sarcoidosis and LCH.

Case 1

A 38 year-old man was admitted in endocrinology department to be explored for central diabetes insipidus. MRI imaging showed multifocal osteolytic lesions in maxillary and mandibular bones, thick pituitary stem and disappearance of the T1 hyper signal from the post pituitary gland. The patient presented normal renal function, normal levels of ACTH and thyroid-stimulating-hormone as well as serum electrolytes (sodium: 137 mmol/l, potassium: 3.8 mmol/l; calcium: 8.8 mg/dl). Mandibular-bone-biopsy and histological findings confirmed the diagnosis of LCH with multi-system bone and post-pituitary involvement. The patient received corticosteroid in combination with vasopressin through the nasal route. He also underwent surgical resection of maxillary lesion and dental prosthesis. Evolution was marked by persistence of diabetes insipidus requiring continued substitution with vasopressin. 3 years later, he presented bilateral mixed hearing loss due to secondary chronic medial otitis and dyspnea. Thoracic CT showed diffuse micro-cystic lesions in the lung parenchyma. High doses of steroids, vinblastine and vasopressin were started. He was lost from sight for 4 years, he stopped treatment except vasopressin. He had persistent deafness. Biological assessment was normal. Radiological assessment showed the same pulmonary, mastoid and mandibular lesions observed 4 years ago. The patient was considered in remission.

Case 2

A 49 year-old women was presented in internal medicine department in 2006 with cutaneous lesions (erythematosis lesions/nodules) in the upper member and the trunk. She suffered from short breath and cough. CT scan showed bilateral hilar lymphnodes enlargement with interstitial lung lesions. Pulmonary function test revealed low static lung volumes with low DLCO. Skin and lymph nodes biopsies revealed granulomas without caseum necrosis. Hormonal evaluation demonstrated decreased thyroid-stimulating hormone secretion with decreased thyroid hormone. Pituitary magnetic resonance imaging revealed thickening of pituitary stalk. Treatment of central hypothyroidism by thyroid hormone replacement was administered. Corticosteroids at the doses of 0.5 mg/kg/day were prescribed for 4weeks followed by progressive tapering with total duration of 4 years.

Conclusion

Central diabetes insipidus canbe related to several etiologies. Rare causes must be kept in mind, especially infiltrative diseases such as sarcoidosis or histiocytosis. Systemic clinical presentation guides usually the diagnosis.