hematology and oncology
Langerhans Cell Histiocytosis
Diagnosis of Langerhans Cell Histiocytosis
Biopsy Langerhans cell histiocytosis is suspected in patients (particularly young patients) with unexplained pulmonary infiltrates, bone lesions, or ocular or craniofacial abnormalities; and in children<2 years with typical rashes or severe, unexplained multiorgan disease. X-rays are often done because of presenting symptoms. Bone lesions are usually sharply marginated, and round or oval, with a beveled edge giving the appearance of depth. However, some lesions are radiographically indistinguishable from Ewing sarcoma of bone , Diagnosis is based on biopsy. Langerhans cells are usually prominent, except in older lesions. These cells are identified by a pathologist experienced in the diagnosis of LCH according to their immunohistochemical characteristics, which include cell surface CD1a, CD207 (langerin), and S-100 (although not specific). Tumor tissue should be tested forBRAFV600Emutation and other MAPK pathway mutations. Once the diagnosis is established, the extent of disease must be determined by appropriate imaging and laboratory studies. Laboratory studies used to define the extent of disease include the following: Complete blood count with differential Comprehensive metabolic panel Coagulation studies Early morning urinalysis Imaging studies include the following: Skeletal survey, including chest x-ray Ultrasonography of the abdomen MRI of the brain (to evaluate the pituitary gland) MRI of the spine MRI or CT of the skull (to look for temporal bone lesions) MRI or CT of the orbit (to look for facial bone lesions) CT of the chest (if the chest x-ray is abnormal) CT or MRI of the abdomen (if examination reveals hepatosplenomegaly or if liver function test results are abnormal) PET/CT if available (because it can identify bone lesions not seen on skeletal survey) 