8110 Lymphocytic Hypophysitis secondary to a ruptured Rathke’s Cleft Cyst complicated by post surgical recurrence: A rare phenomenon

Abstract Disclosure: M.S. Maharaul: None. F. Thelmo: None. I. Ahmed: None. Introduction: Lymphocytic hypophysitis secondary to ruptured Rathke’s cleft cyst (RCC) is a rare entity. Rathke’s cleft cysts are benign fluid-filled intra-sellar cysts that originate from the remnants of Rathke’s pouch and contain mucoid material. Most are asymptomatic; some may get symptomatic during cyst expansion and rupture releasing liquid content and trigger local inflammation. Surgical resection followed by glucocorticoids is usually curative. Case: A 42-year-old female presented to the hospital with one week history of right sided frontal headache associated with blurred vision in right eye. MRI Brain showed a 15 mm complex cystic lesion in the sella with suprasellar extension associated with peripheral calcifications. On admission, endocrine laboratory investigations including pregnancy test were normal. Ophthalmic testing did not reveal any acute abnormalities. Transsphenoidal surgery was performed for tumor resection. Pathology examination revealed infiltration of massive lymphocytes, macrophages, plasma cells, and eosinophils that were diagnostic of lymphocytic hypophysitis in the anterior pituitary lobe. She was started on glucocorticoids and discharged home. Rheumatology and Infectious diseases workup were unrevealing. On follow up 3 weeks later, she had self-discontinued steroids. The following week, she presented to the emergency room again with a right sided headache and blurred vision. MRI Brain revealed a 16 mm recurrent inflammatory mass lesion in the sella. Endocrine panel demonstrated an 8 am serum cortisol level of 7.4 mcg/dl, ACTH 20 pg/ml, FSH 6.2 mIU/ml, LH 4.9 mIU/ml, free T4 1.1 ng/dl and prolactin 8 ng/ml. She underwent transsphenoidal resection of the mass again and was restarted on glucocorticoids. This time pathology examination revealed an epithelial lined cyst most compatible with Rathke’s cleft cyst. She continued to remain on a glucocorticoid taper during the follow up period. On re-evaluation, her endocrinology laboratory investigations continued to show a deficiency of gonadotropins for which she is following up with OBGYN, but the remaining pituitary hormones were all within normal limits. Conclusion: Rathke’s Cleft Cysts (RCCs) should be in the differential diagnoses for evaluation of hypophysitis. There have only been a handful of cases in the literature of hypophysitis associated with a ruptured RCC, and only one case of recurrence after surgical debulking. This case provides an insight into the clinical behavior, diagnosis, and timely management of lymphocytic hypophysitis due to a ruptured Rathke’s cleft cyst and management post-recurrence. Presentation: 6/3/2024