LAUSR

Introduction: Langerhan cell histiocytosis (LCH) is a rare cause of eosinophilic granulomatous inflammation that can affect multiple organ systems, mainly diagnosed in children. Hypothalamic-pituitary axis involvement is well established and is the characteristic intracranial manifestation of LCH. Patients can present with several presentations including anterior pituitary axis failure; however, the most common presentation is Diabetes Insipidus (DI). Here, we present a rare case of isolated pituitary LHC in male adult. Clinical Case: 47 years old gentleman presented with 4 week history of insidious headaches associated with persistent nausea. He also noticed drooping of his left eyelid and presented to hospital with complete ptosis. His CT head did not show any abnormalities. However finding on his MRI brain were consistent with a central skull base inflammatory process centred on the pituitary, extending cranially to the chiasm and third ventricular floor as well as laterally to the cavernous sinuses. His anterior pituitary profile was as follow: LH - 0.7 U/L (1.2-8.6 U/L), FSH - 4.2 U/L (1.3-19.3 U/L), Testosterone - <0.3 nmol/L (6.1 - 27.1 nmol/L), IGF-1 - 9.8 (8.8-31), Prolactin - 197 mIU/L (56-278 mIU/L), TSH - 1.18 mU/L (0.38 - 5.33 mU/L), FT4 - 4.4 pmol/L (8.4 - 19.1 pmol/L). He underwent a Short Synacthen test with a baseline cortisol of 19 nmol/L, rising to 100 nmol/L at 30 minutes and 130 nmol/l at 60 minutes. Following initiation of high dose steroid replacement (Prednisolone 15 mg daily), Levothyroxine and Testosterone, his Prednisolone was slowly weaned to 4 mg once a day in line with an improvement in his ptosis & left temporal hemianopia. His pituitary biopsy showed infiltrates of abundant histiocytes and inflammatory cells (lymphocytes). Histiocytes were organised in a granulomatous fashion with multinucleated giant cells and eosinophils (CD 68 staining positive). Langerin stain (positive) / S100 stain (some) / CD1a (few) - cells positive, confirming a diagnosis of LCH. Additional CT (chest/abdomen/pelvis) and PET imaging confirmed no additional organ involvement. Conclusion: LCH is a rare cause of anterior pituitary failure. Limited information regarding treatment for isolated pituitary LCH is available. This case suggests that a conservative approach to successful treatment with steroids can be considered.