[A female patient with earache, polyuria and polydipsia]. / Eine Patientin mit Ohrenschmerzen Polyurie und Polydipsie.

INTRODUCTION: Langerhans cell histiocytosis is a rare inflammatory bone marrow neoplasia that frequently affects bone, lung, skin and pituitary gland. Due to its broad spectrum of clinical presentation, an appropriate diagnosis might be difficult. HISTORY: A 54-year-old female patient complained of pain in her right ear for 5 months. On account of similar complaints, a mastoidectomy had already been performed 3 years ago. Histology at that time revealed nonspecific inflammation. Furthermore, she reported excessive thirst. FINDINGS AND DIAGNOSIS: Computed tomography of the temporal bones showed osteolysis in the mastoid. Magnetic resonance imaging and bone scintigraphy assessed these changes as uncharacteristically inflammatory. Polydipsia proved to be a symptom of central diabetes insipidus in the water deprivation test. Finally, remastoidectomy provided histologic evidence of Langerhans cell histiocytosis. THERAPY AND COURSE: Besides systemic chemotherapy with cytarabine, the patient also received denosumab and desmopressin. CONCLUSION: Langerhans cell histiocytosis involving cranial bones is often associated with diabetes Insipidus. Knowledge about the distinctive constellation may lead to a more rapid diagnosis and improved prognosis.