O-01 A CASE OF LANGERHANS CELL HISTIOCYTOSIS WITH INVOLVEMENT OF THE HYPOTHALAMUS, BONE, AND LIVER
Authors: Acar Saadet , Canturk Zeynep , Çetinarslan Berrin , Selek Alev , Gezer Emre , Sözen Mehmet , Alkan Özlem , Öktem Fatma , Karaca Büşra 
Published: January 2025

Abstract

Introduction
Langerhans cell histiocytosis (LCH) is a neoplastic disorder characterized by the abnormal infiltration of Langerhans cells, affecting multiple systems. Here, we report a rare case of LCH with involvement of the hypothalamus, liver, and bone.

Clinical Case
A 36-year-old female patient presented to the psychiatry department with complaints of anxiety, including sudden behavioral changes, headaches, increased forgetfulness, hypersomnia, and excessive thirst excessive eating, and memory lapses that persisted for three months. A contrast-enhanced pituitary MRI taken revealed a lobulated mass lesion, measuring 15x9x17 mm, extending into the interpeduncular cistern and anteriorly toward the optic chiasm, with cystic necrotic areas located at the base of the third ventricle (Figure 1A). Laboratory examinations indicated panhypopituitarism and central diabetes insipidus. Abdominal ultrasound revealed a hypoechoic area in liver segment 8.PET-CT showed a region of intense metabolic activity in the posterior section of the left mastoid bone (SUVmax: 12.4). In addition, a 14-mm focal area with increased fluorodeoxyglucose uptake was observed in liver segment 8 (SUVmax: 8.4) (Figure 1B).The temporal MRI showed a mass lesion extending to the petrous apex, filling the mastoid cells on the left side, with signal characteristics similar to the hypothalamic lesion (Figure 1C).Biopsy was performed on identified lesions. Both biopsy results were consistent with LCH. She was planned to administer two courses of cladribine therapy. Follow-up PET-CT after chemotherapy indicated that the liver and mastoid bone involvement had resolved. However, the patient’s neuropsychiatric symptoms did not improve following chemotherapy. Paraneoplastic autoimmune encephalitis was primarily suspected, and antibody testing was performed. Due to the progressive nature of the patient’s condition, intravenous immunoglobulin therapy was administered. On the fourth day of this treatment, the patient experienced increased agitation and delusions, and developed disorientation.50 mg of quetiapine was prescribed. Three days after starting quetiapine, the patient developed fever, tachypnea, muscle rigidity, increased confusion, and an acute increase in serum creatine kinase levels (29,000 U/L). The condition was evaluated as a neuroleptic malignant syndrome leading to the discontinuation of quetiapine. The patient was transferred to the intensive care unit (ICU).On the first day of ICU admission, the patient was intubated. Despite cardiac support, the patient died on the third day of ICU admission.

Conclusion
LCH is a rare but multisystemic inflammatory neoplasm. The absence of specific clinical features can lead to delays in diagnosis. Although LCH most commonly presents with bone and skin lesions, a multidisciplinary approach is crucial for an accurate diagnosis. Albeit rare, LCH should be considered in the differential diagnosis of patients presenting with hypothalamic masses.Figure 1:Magnetic resonance image of the hypothalamic mass (A), Magnetic resonance images revealing a mass lesion in the left mastoid bone (B) and a subcapsular lesion in liver segment 8 (C)