Endocrine Abstracts

Introduction: IgG4 Related Hypophysitis (IgG4-RH) is a newly recognized form of hypophysitis. It usually appears as part of IgG4-Related Disease (IgG4-RD), an immune mediated disease, with manifestations in many organs. Isolated hypophysitis without other IgG4-RD manifestations is rare.

Presentation: A 64 years old female referred to our department for further investigation of a 9 month history of fatigue, muscle weakness, recurrent episodes of right temporal headaches, anorexia and weight loss and a month’s history of diplopia and right eyelid ptosis. Past medical history was unremarkable. On clinical examination there was marked proximal muscle weakness, right eyelid ptosis, diplopia, but visual fields were normal. Laboratory evaluation revealed hypopituitarism of the anterior pituitary lobe. Magnetic resonance imaging (MRI) showed a thickened pituitary stalk and an enlarged heterogenous pituitary gland with expansion to the right cavernous sinus. IgG4 levels were elevated (192 mg/dl, normal values: 8–140 mg/dl). Based on these findings the diagnosis of IgG4-RH was made. The patient was commenced on prednisolone 40 mg/day and thyroxine. A remarkable clinical improvement was observed within the first forthnight. Three months later she had no diplopia, no muscle weakness and repeated MRI of her pituitary gland showed great improvement of the previous picture. IgG4 levels were reevaluated and were found to be reduced.

Conclusion: Isolated IgG4-RH is a rare entity. IgG4 levels should be obtained in cases suggestive of hypophysitis. Corticosteroid treatment greatly improves the clinical picture.