MON-130 A Case of Recurrent Pituitary Adenoma Associated With IgG4- Related Disease

Abstract Disclosure: M. Kawji: None. Abstract: IgG4-RD related disease is a systemic autoimmune disease with distinctive histopathology, the term first time used in 2001 when describing the first case of sclerosing pancreatitis. we present a case of IgG4- hypopituitarism presented as a recurrent of pituitary macroadenoma. Case presentation 61-year-old male with underlying non function pituitary macroadenoma status post pituitary tumor resection in 2013 followed by fractionated radiation therapy. Final pathology read as possible adenoma with slightly positive stain for ACTH, PRl, GH. His course complicated with hypopituitarism including secondary adrenal insufficiency on prednisone 5 mg daily, central hypothyroidism on levothyroxine 125 mcg daily and hypogonadism on testosterone cypionate. He has been stable on above regimen and following with periodic MRI imaging over 10 years, his most recent MRI revealed stable residual seller mass approximately 1.1cm x 1 cm. In February 2023 He presented to pituitary- neurosurgery clinic with severe headache for one week followed by right eye diplopia, and ptosis 2 days ago. Clinical exam positive for right oculomotor third nerve palsy, no focal weakness or other neurological symptoms. His brain MRI revealed slightly increased in pituitary mass 1.5 cm x 1.2 cm with superior extension to optic chiasm. Subsequently patient was admitted to the hospital for second endonasal pituitary tumor resection. Final pathology revealed chronic hypophysitis with increased IgG 4- positive plasma cell. He has been seen by neuro immunology clinic for further evaluation of IgG4 related disease. His IgG 4 level was 65 (NR: 2-121) mg/dl , normal GFR with urine protein creatine ratio 0.09 ( NR< 0.19). Extensive workup including hepatitis panel, ANA, HIV, syphilis, SPEP, QuantiFERON gold came back unremarkable. Postoperatively his vision improved slightly, he has begun using prism glasses and is doing convergence exercises. Discussion: IgG4- hypophysitis is a rare disease with less than 100 cases reported in literature. Histopathology finding of lymphoplasmacellular infiltrate with high numbers of IgG4- positive plasma cells confirm the diagnosis. IgG4 levels were normal in most cases of IgG 4-hypophysitis. Glucocorticoid has been used as an initial therapy for IgG 4 related disease. Immunosuppressant agents/rituximab has been used in refractory cases. Conclusion: It is crucial for physicians to thoroughly review pathology cases of pituitary diseases, particularly when unusual presentations are encountered. Ongoing, close follow up is essentials to monitor disease progression, adjust treatment plans, and mitigate potential complications. Presentation: Monday, July 14, 2025