Background: Auto-immune pancreatitis (AIP) is a rare chronic inflammatory disease, characterised by raised serum levels of IgG4, which may mimic pancreaticobiliary malignancy, and is noted to have an IgG4-positive plasma cell infiltrate on pancreatic histology. Extrahepatic manifestations in liver, kidneys, and retroperitoneum, are increasingly recognised.
We present a case of extrapancreatic manifestation of AIP in the pituitary gland causing lymphocytic hypophysitis leading to panhypopituitarism.
Case history: A 67-year-old man presented with obstructive jaundice. A diagnosis of AIP/IgG4-associated cholangitis was made based on imaging, serology and biopsy. Oral steroids and azathioprine led to resolution of jaundice and normalisation of liver function tests. Steroids were weaned and stopped over 6 months with maintenance azathioprine. He presented again with weakness and malaise. Examination revealed heart rate 80 bpm, blood pressure 80/40 mmHg, but no other signs of note.
|Random cortisol||<20 mol/l||<140 nmol/l||Adrenal insufficiency (assumed secondary to prolonged steroid use)|
|TSH||0.7 mIU/l||0.274.2 mIU/l||Panhypopitutiarism|
|T4||7.2 pmol/l||1222 pmol/l|
|LH||<0.1 IU/l||1.78.6 IU/l|
|FSH||0.8 IU/l||1.512.4 IU/l|
|Testosterone||<0.1 nmol/l||9.927.8 nmol/l|
|Serum osmolality||300 mOsmol/kg||285295 mOsmol/kg|
|Urine osmolality||263 mOsmol/kg||300900 mOsmol/kg|
Gadolinium-enhanced MRI showed significant enlargement and infiltration of the pituitary stalk, consistent with inflammation. Hormone replacement led to resolution of symptoms. Prednisolone 30 mg was re commenced with complete resolution of the pituitary infiltrate on repeat gadolinium MRI 6 weeks later. He remained clinically well.
Autoimmune pancreatitis is now recognised as a disease which can occur globally.Extra-pancreatic disease is increasingly recognised as a common feature, and there have been two other case reports of lymphocytic hypophysitis in AIP. Early recognition of this is important in rational management of these patients.