Purpose or Case Report: Langerhans cell histiocytosis (LCH) is an inflammatory myeloid tumor, a rare disease that is most often diagnosed in early childhood.
Here, we present the radiological spectrum of manifestations of this disease. The organs most frequently affected are the bone, skin, central nervous system (CNS), lungs, bone marrow, liver, spleen and lymph nodes.
Our review includes illustrations of the regression of severe lung lesions and neurodegenerative lesions, which can be observed under targeted therapy (mitogene-activated protein kinase inhibitor).
In addition, for each lesion, we present a short list of differential diagnoses.
Bone
Langerhans cell histiocytosis is a potentially multisystem disease, but its most common presentation is a single-bone lesion. It predominantly affects the axial skeleton, with the skull being the most frequently affected bone. Bone lesions generally develop slowly and can sometimes be aggressive.
Vertebra plana is a classic aspect of vertebral LCH ; spinal cord compression is rare.
Langerhans cell histiocytosis of the ear primarily affects the mastoid. The ossicles, petrous apex and inner ear are rarely affected.
Central nervous system
The pituitary stalk is the most commonly affected anatomical region. Other affected sites include the infra- and supratentorial parenchyma, venous sinuses, dura mater, and ventricules. Neurodegenerative lesions are distinct from other LCH lesions and have an affinity for the dentate nucleus, cerebellar white matter, brainstem, and basal ganglia.
Lung
The initial lung lesions are nodules that gradually excavate to form thin-walled cysts that fuse and may lead to pneumothorax. Pulmonary fibrosis is a late stage of the disease.
At risk organs
The liver, spleen, bone marrow, and lymph nodes are affected in Letterer-Siwe syndrome, which occurs in infancy. Chronic hepatobiliary LCH is characterized by sclerosing cholangitis that can progress to biliary cirrhosis.
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