W017

IgG4 related hypophysitis-a diagnostic challenge

P Machenahalli, N Hill, A Mehta, N Mendoza, P Lewis, C Pusey, N M Martin, K Meeran, F Wernig, E Hatfield, Charing Cross Hospital, London

Introduction: Isolated IgG4 related hypophysitis is a rare condition. Headache, visual field defects, pituitary hormones insufficiency are the main clinical features. There a few diagnostic challenges as MRI findings might mimic other conditions. Pituitary biopsy is the gold standard investigation.

Case Presentation: A 34 year old lady presented with headache, blurred vision. MRI brain revealed pituitary macroadenoma (19x15x11mm elevating the optic chiasm). She has been on Progesterone only pill for some years so didn’t have regular periods. She had 2 children with no further plans of pregnancy. Biochemical workup revealed Prolactin 1076 milliunit/L, Cortisol 50 nmol/L, TSH-0.22 milliunit/L, FT4-4.4 pmol/L, LH <0.5IU/L, FSH-1.7 IU/L, Oestradiol <70 pmol/L. RA factor, complements normal, ANA, ANCA negative, IgG4 1.53g/L (<1.3), chest x-ray was normal. She was commenced on Hydrocortisone and Levothyroxine. Has complained of polyuria and polydipsia. Water deprivation test confirmed Cranial Diabetes Insipidus, she was commenced on Desmopressin.

She underwent Pituitary biopsy as per the recommendation of pituitary MDT. Histopathology of the specimen revealed initial diagnosis of Lymphocytic Hypophysitis. Further immunostaining revealed IgG4 related disease. She has been commenced on Prednisolone 60 mg OD with gradual down titration to a maintenance dose. Has been referred to a specialist with an interest in IgG4 related disease for the consideration of immunotherapy. Repeat MRI Pituitary has revealed reduction the size of the pituitary macroadenoma.

Conclusion: IgG4 related disease commonly presents with multisystem involvement. Literature review reveals only a few cases of isolated IgG4 hypophysitis. Misdiagnosis can be avoided by a careful and dedicated cytological analysis. 

References:

Revisitation of autoimmune hypophysitis: knowledge and uncertainties on pathophysiological and clinical aspects. Pituitary 2016, Aug 8