Case Report: IgG4-Related Disease Presenting With Isolated Hypophysitis

IgG4-related disease (IgG4-RD) is an immune-mediated condition that affects multiple organs, including the pituitary gland. Here we present a patient with isolated pituitary involvement of IgG4-RD mimicking pituitary apoplexy.

A 49-year-old woman presented to the emergency department with abdominal pain, nausea, vomiting, and weight loss. Her blood pressure was low, and she appeared euvolemic with the rest of physical examination being noncontributory. Her electrolytes showed low serum sodium of 118 mmol/L (normal 135-145). Further investigations were significant for low morning cortisol of 20 nmol/L (N:100-500) and low adrenocorticotropic hormone. Magnetic resonant imaging of the pituitary fossa showed a pituitary macroadenoma with hemorrhagic transformation. She was started on glucocorticoids and levothyroxine before undergoing surgical removal of the pituitary tumor. The pathology was positive for IgG-4-related hypophysitis (IgG4-RH) with no evidence of pituitary tumor.

IgG4-RD is an immune-mediated condition that can affect many organs including the pituitary gland, in the form of hypophysitis. IgG4-RH can affect anterior, posterior, or both pituitary lobes. In 2011, Leporati et al developed a diagnostic criteria for IgG4-RH which includes the following: imaging, serology, histopathology, and response t glucocorticoids. The mainstay of treatment is glucocorticoids and hormone replacement therapy.

IgG4-RH might be underestimated and should be suspected in those with hypophysitis or unknown cause of hypopituitarism. Moreover, pituitary macroadenoma with hemorrhagic transformation and panhypopituitarism should be considered as rare and unusual presentations of IgG4-RD.