Clinicoradiological Discrepancy in Multisystem Langerhans Cell Histiocytosis with Central Nervous System Involvement.

Langerhans cell histiocytosis (LCH) is a rare neoplasm that is caused by an uncontrolled proliferation of Langerhans cells. The clinical presentation of LCH is heterogeneous and can manifest as single or multiple osteolytic lesions, skin ulcerations, and involvement of single or multiple systems. Central nervous system (CNS) involvement is reported in 3.4-57% of patients with multisystem disease. In this article, we present the case of a young man with single system involvement (bone) of LCH who presented with seizures, headache, papilledema, and tinnitus. His magnetic resonance imaging (MRI) of the brain findings were reported as a normal study. The subtle signs of CNS involvement were missed by the radiologist. However, the high index of suspicion resulted in early diagnosis and treatment. The presence of empty sella turcica in neuroimaging could be the first sign of intracranial disease with chronic intracranial hypertension associated with LCH. This is especially correct if previous computed tomography (CT) scan of the brain was normal with normal appearance of the pituitary gland and the sella. Neuroimaging films should be reviewed by an expert neuroradiologist. In patients with new neurological symptoms who were diagnosed previously with LCH, intracranial disease has to be excluded. The workup in such case should include an MRI of the brain, CT of the brain and temporal bones, bone scan, cerebrospinal fluid analysis, ophthalmological assessment, and measurement of intracranial pressure. In patients with LCH who present with symptoms and signs of raised intracranial pressure, the term idiopathic intracranial hypertension should not be applied until an intracranial disease has been excluded totally. Keywords: Langerhans Cell Histiocytosis; Central Nervous System Involvement; Neuroimaging; Intracranial Hypertension.