Endocrine Abstracts

A 68-year-old female was found to have a supra sellar mass on CT scanning for investigation of long-standing tremor. She had experienced thirst, polydipsia, polyuria, nocturia and malaise for 1 year. Primary hypothyroidism had been diagnosed 5 years earlier. A left temporal visual field defect found 3 years earlier had been attributed to a structural anomaly of the optic nerve head. MR scanning confirmed the presence of a mass lesion of the infundibulum with displacement of the optic chiasm.

Investigations: Visual fields revealed progression of the left visual field defect plus a right field defect. Anti-thyroid peroxidase antibodies >500 IU/ml, anti-nuclear antibodies 1:1280, fT₄ 21 pmol/l, fT₃ 6.2 pmol/l, TSH <0.02 mU/l (taking thyroxine 75 μg od), cortisol (0900 h) 448 nmol/l, FSH 0.5 U/l, LH 0.1 U/l, prolactin 4379 μIU/ml, IGF1 4.5 nmol/l, plasma osmolality 317 mOsmol/kg and urine osmolality 226 mOsmol/kg. Short Synacthen test: cortisol 0 min (0900) 244, 30 min 651 and 60 min 767 nmol/l. Metoclopramide test: prolactin 0 min 4126, 30 min 5465 and 60 min 4951 μIU/ml. CSF: protein 1.3 g/l, white blood cells 130/mm³ (95% lymphocytes), ACE normal, AFP and HCG not measurable.

Impression: History, physical signs and investigations suggestive of chronic lymphocytic infundibulitis of at least 3 years duration. Treatment: methylprednisolone 250 mg i.v. daily for 3 days resulted in improvement in visual fields and shrinkage of the infundibular mass. Oral prednisolone 30 mg daily decreasing to 15 mg daily over 2 months resulted in further improvement in visual fields, pituitary function and diabetes insipidus with normal appearance of the infundibulum. We describe a new variant chronic form of lymphocytic infundibulitis with a good therapeutic response to glucocorticoid treatment.