Endocrine Abstracts

Introduction: Langerhans cell histiocytosis (LCH) is a multi-organ disease characterized by clonal proliferation of immature dendritic cells. Isolated hypothalamo-pituitary (HP-LCH) involvement is rare and the coexistence of empty sella syndrome (ESS) is even rarer. We report a case of LCH with ESS and adipsia presenting as life-threatening hypernatremia.

Case presentation: A previously healthy 26-year-old woman presented with amenorrhea, headaches, somnolence, high-grade fever, altered behavior, cognitive decline and inability to recognize relatives. Her relatives noted her loss of thirst sensation. She was delirious and dehydrated with initial investigations revealing hypernatremia (Na-172 mEq/l) with Acute Kidney Injury (Urea-48 mg/dl, Creatinine-1.97 mg/dl), Serum Osmolality 387-mOsm/kg and Urine Osmolality-747 mOsm/kg. Fluid replacement uncovered the co-existing Arginine Vasopressin deficiency (AVP-D). MRI Brain showed T1/T2 iso-intense heterogeneously enhancing irregular suprasellar lesion (2.6 × 1.9 × 2 cm) with loss of interface with hypothalamus, basal ganglia and midbrain, partial empty sella and absent posterior pituitary bright spot. Anterior pituitary workup revealed 8 am cortisol-1.36 mg/dl, TSH-2.312 mIU/l, fT4-0.46 ng/dl, fT3-2.03 pg/ml, Prolactin-0.25 ng/ml, IGF-1-55.42 ng/ml, FSH-0.59 mIU/ml, LH-<0.01 mIU/l. Serum and CSF AFP and HCG were negative. Hormonal treatment was initiated. Whole-body PET-CT showed FDG-avid (SUVmax-25.56) well-defined suprasellar irregular soft tissue density, measuring 1.5 × 2 cm. Stereotactic diagnostic Brain Biopsy was performed. IHC was strongly positive for CD1a, compatible with LCH. 20Gy/10# Radiotherapy (RT) given using VMAT Technique. 6 weeks post RT, her cognition and thirst sensation has returned and 30% radiological improvement was noted.

Conclusion: LCH should be considered in cases of adipsia with AVP-D, even in the absence of other systemic features. Isolated HP-LCH can easily be misdiagnosed; therefore, a biopsy is necessary for an accurate diagnosis to initiate timely and targeted therapy. Adipsia with cognitive impairment led to life-threatening hypernatremia, posing significant management challenges that required ongoing caregiver counseling and support. This case highlights the essential role of a multidisciplinary approach in navigating the complexities of this disease.