The complete evaluation of any patient, whether presenting with single system or multisystem disease, should include the following:

• Blood tests: Blood tests include complete blood count with leukocyte differential and platelet count, liver function tests (e.g., bilirubin, albumin, aspartate aminotransferase, alkaline phosphatase, prothrombin time/partial thromboplastin time in patients with hepatomegaly, jaundice, elevations of liver enzymes or low albumin), and serum electrolytes.



• Urine tests: Urine tests include urinalysis and a water-deprivation test if diabetes insipidus (DI) is suspected.



• Bone marrow aspirate and biopsy: The bone marrow aspirate and biopsy should be stained with anti-CD1a and/or anti-CD207 (langerin) for patients with thrombocytopenia or anemia not explained by other causes.



• Neurologic exam



• Radiologic and imaging tests: Radiologic tests include skeletal survey, skull series, positron emission tomography (PET) or bone scans, chest x-ray, and computed tomographic (CT) scan of the head (if orbital or mastoid involvement is suspected). Imaging tests may include magnetic resonance imaging (MRI) scan with gadolinium contrast of the brain for patients with DI or suspected neurologic involvement.[1]

  A CT scan of the lungs is indicated for patients with abnormal chest xrays or pulmonary symptoms. High-resolution CT scans may show evidence of pulmonary Langerhans cell histiocytosis (LCH) when the chest x-ray is normal, thus in infants and toddlers with normal chest x-rays, a CT scan may be considered.[2] LCH causes fatty changes in the liver or hypodense areas along the portal tract, which can be identified by CT scans.[3] Newer diagnostic imaging modalities, such as somatostatin analogue scintigraphy or F18-FDG PET scans, which augment these standard methods may prove useful.[4-6] PET scans may be helpful in following the response to therapy since the intensity of the PET image diminishes with healing of a bone or other lesion.[7,8]

  MRI findings of central nervous system LCH include enhancement of the pons, basal ganglia, and white matter of the cerebellum, as well as mass lesions or meningeal enhancement. In a report of 163 patients,[7] meningeal lesions were found in 29% and choroid plexus involvement in 6%. Paranasal sinus or mastoid lesions were found in more than 50% versus 20% of controls, and accentuated Virchow-Robin spaces in 70% of patients versus 27% of controls.




• Biopsy: Lytic bone lesions, skin, and lymph nodes are the most frequent lesions biopsied for diagnosis of LCH. The Langerhans cells (LCs) should stain with antibodies to CD1a or anti-langerin (CD207) to confirm the diagnosis of LCH. CD1a is more specific for LCH than antilangerin, since normal dendritic LCs in lymph nodes and liver may stain for CD207, but not CD1a.[9] Since other types of histiocytes and macrophages may stain with S-100, this, and morphology of hematoxylin and eosin stained sections, are not considered sufficient to establish the diagnosis of LCH.[9] A liver biopsy is indicated when a child with LCH presents with hypoalbuminemia not caused by gastrointestinal LCH or other etiology. These patients may not have elevated levels of bilirubin or liver enzymes. An open lung biopsy is the preferred method of obtaining tissue for diagnosis of pulmonary LCH as bronchoalveolar lavages may be nondiagnostic.

References

1. Grois N, Prayer D, Prosch H, et al.: Course and clinical impact of magnetic resonance imaging findings in diabetes insipidus associated with Langerhans cell histiocytosis. Pediatr Blood Cancer 43 (1): 59-65, 2004.  [PUBMED Abstract]
   
   
2. Ha SY, Helms P, Fletcher M, et al.: Lung involvement in Langerhans' cell histiocytosis: prevalence, clinical features, and outcome. Pediatrics 89 (3): 466-9, 1992.  [PUBMED Abstract]
   
   
3. Prasad SR, Wang H, Rosas H, et al.: Fat-containing lesions of the liver: radiologic-pathologic correlation. Radiographics 25 (2): 321-31, 2005 Mar-Apr.  [PUBMED Abstract]
   
   
4. Calming U, Jacobsson H, Henter JI: Detection of Langerhans cell histiocytosis lesions with somatostatin analogue scintigraphy--a preliminary report. Med Pediatr Oncol 35 (5): 462-7, 2000.  [PUBMED Abstract]
   
   
5. Calming U, Bemstrand C, Mosskin M, et al.: Brain 18-FDG PET scan in central nervous system langerhans cell histiocytosis. J Pediatr 141 (3): 435-40, 2002.  [PUBMED Abstract]
   
   
6. Binkovitz LA, Olshefski RS, Adler BH: Coincidence FDG-PET in the evaluation of Langerhans' cell histiocytosis: preliminary findings. Pediatr Radiol 33 (9): 598-602, 2003.  [PUBMED Abstract]
   
   
7. Prayer D, Grois N, Prosch H, et al.: MR imaging presentation of intracranial disease associated with Langerhans cell histiocytosis. AJNR Am J Neuroradiol 25 (5): 880-91, 2004.  [PUBMED Abstract]
   
   
8. Phillips M, Allen C, Gerson P, et al.: Comparison of FDG-PET scans to conventional radiography and bone scans in management of Langerhans cell histiocytosis. Pediatr Blood Cancer 52 (1): 97-101, 2009.  [PUBMED Abstract]
   
   
9. Chikwava K, Jaffe R: Langerin (CD207) staining in normal pediatric tissues, reactive lymph nodes, and childhood histiocytic disorders. Pediatr Dev Pathol 7 (6): 607-14, 2004 Nov-Dec.  [PUBMED Abstract]
   
   

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