Endocrine Abstracts

Introduction

Cerebral tuberculomas are a rare form of tuberculosis due to the hematogenous spread of Mycobacterium Tuberculosis (MT). Pituitary localization is exceptionally uncommon with total reported cases in the literature fewer than a hundred. Symptoms and radiologic features are nonspecific, leading sometimes to misdiagnosis. We report the rare case of a patient diagnosed with a primary pituitary stalk tuberculosis.

Observation

A 37-year-old woman was referred to our department for a suspected diabetes insipidus. A CREST syndrome treated by oral corticotherapy (10 mg of Prednisone) and benzodiazepin (120 mg of Diltiazem) marked her past medical history. She presented with a recent polyuria-polydipsia syndrome with about 10liters/day. No menstrual disorders were reported. Pituitary MRI showed a marked thickening of the pituitary stalk with nodular enhancement suggestive of granulomatosis. A water deprivation test confirmed the central diabetes insipidus with a rise in urine osmolarity after desmopressin administration and low arginine vasopressin (AVP) levels (< 0.5 pmol/l). The etiological diagnostic procedure begins with the search for possible other lesions suggestive of histiocytosis, sarcoidosis, tuberculosis or other etiologies elsewhere in the body that could be more easily biopsied, particularly because the biopsy of the stalk is difficult, harmful and often not contributive. We performed neck, thorax, abdomen, and pelvis CT scan, measurement of serum markers such as B2 microglobulin, angiotensin converting enzyme, anticytoplasmic antibodies and salivary gland biopsy.Tuberculin skin test (TST) showed a positive response with a skin reaction of 12 mm (> 10 mm). The pathological proof of the pituitary tuberculosis was thus obtained indirectly considering high tuberculosis endemicity in Tunisia, raw milk consumption and positive TST. Our patient was put on anti tuberculosis treatment and desmopressin substitution. Follow up MRI (3 months after tuberculosis medication stopped) showed complete resolution of the granuloma but with diabetes insipidus persistence.

Discussion and conclusion

Pituitary tuberculosis is an uncommon form of intra-cranial tuberculosis. Isolated pituitary tuberculosis in extremely rare and difficult to diagnose. The case we studied showed the difficulties encountered in the diagnosis of a thickened pituitary stalk.