Complete Resolution of the Pituitary Mass Lesion and Improvement of Pituitary Function with Corticosteroid in Autoimmune Hypophysitis: A Case Report

BACKGROUND: Autoimmune hypophysitis is the consequence of an immune-mediated inflammation of the pituitary gland, which is rare, and most frequently occurs in females during postpartum periods. It usually responds well to corticosteroid treatment with reported resolution of the pituitary mass lesion. CASE REPORT: A 51 years male presented with a one-month history of lethargy, headache, nausea, proximal muscle weakness with intermittent flushing. He was a diabetic with metformin 500mg twice daily. No other remarkable medical history or family history of autoimmune disease. On examination, he had no neurological deficit with a normal visual field. His initial biochemical evaluation showed features of secondary hypothyroidism as evidenced by low free FT4 and suppressed TSH with normal electrolytes. The subsequent evaluation of his hormonal profile revealed panhypopituitarism. Contrast MRI of pituitary showed an enhanced homogenous mass and minimal stalk thickening with a dural tail and preserved posterior bright spot. He was managed with glucocorticoid 20 mg once daily for two weeks along with levothyroxine and testosterone replacement. After two weeks of treatment, he improved clinically. Repeat MRI imaging of the pituitary showed complete resolution of the homogenous mass. CONCLUSION: Although autoimmune hypophysitis is rare in males, a careful clinical history with necessary hormonal investigations is required for the suspicion about the inflammatory pituitary disorders This current case highlights glucocorticoid as the primary modality of treatment and the need for long-term follow-up with periodic clinical assessment.