(20.13) A Race Against Time: Early Diagnosis and Prompt Management of IgG4 Related Hypophysitis.

IgG4 related hypophysitis (IgG4 RH) is a rare infiltrative cause of hypopituitarism, and if not recognized and treated promptly, can lead to pituitary fibrosis and atrophy. The diagnosis mainly depends on pituitary biopsy that could potentially cause permanent hypopituitarism. We report an atypical case in which meticulous biochemical workup and imaging lead to prompt management, leading to complete resolution of symptoms without the need for an invasive procedure.

Case(s) Description :

A 37-year-old female presented to ER for new onset left diplopia, ptosis, and headache. Physical exam confirmed left third and sixth cranial nerve palsy. MRI brain showed a large enhancing sellar mass with asymmetric extension into the cavernous sinuses, encasing bilateral internal carotid arteries and mass effect on right internal carotid artery. Labs showed normal chemistry and CBC, AM cortisol 1.8 ug/dL, ACTH 20 pg/ml, TSH 0.92 mIU/ml, FT4 0.48 ng/dL, prolactin 132 ng/ml, LH 0.20 mIU/ml, FSH 0.80 mIU/ml, and IGF-1 89 ng/ml. ESR and CRP were elevated. ANCA vasculitis, Sarcoidosis, Tuberculosis, and HIV were ruled out. Serum IgG4 was elevated to 185 mg/dl (1-123). Lumbar puncture for CSF analysis confirmed a high IgG index of 0.84 (< 0.66). IgG4 hypophysitis was diagnosed given clinical presentation, diffuse pituitary enlargement on imaging, and an elevated IgG4 level. Patient was treated with high dose intravenous steroid with significant improvement within two days, and then transitioned to oral steroids. She was discharged home on prednisone and levothyroxine. Repeat MRI one month later showed resolution of pituitary inflammation. Clinically, she was asymptomatic, and pituitary function improved as well. Given excellent clinical response to steroids, an invasive pituitary biopsy was not required.

 

Discussion :

This atypical case of a young woman presenting with IgG4 RH portrays insights into diagnosis and treatment of this rare condition. Clinical manifestations can range from endocrine dysfunction to mass effect and compression of the optic chiasm. ACTH deficiency and secondary hypothyroidism are most commonly reported. The strongest predictor of an inflammatory process along with clinical presentation is stalk thickening. High dose steroids should be trialed in suspected patients as it may lead to resolution of pituitary inflammation. Despite pituitary histopathology being the gold standard for diagnosis of IgG4 RH, we present a non-invasive diagnostic approach without the risk of causing biopsy-induced panhypopituitarism. In cases of IgG4 RH, an expectant approach with thorough laboratory assessment and imaging can guide management options with the potential to avoid an invasive pituitary biopsy.