How is polyostotic sclerosing histiocytosis diagnosed?

Updated: Sep 16, 2020
  • Author: Cameron K Tebbi, MD; Chief Editor: Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP  more...
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Answer

The diagnosis of polyostotic sclerosing histiocytosis depends on the area of involvement. Due to the rarity of this disease, the diagnosis can be difficult and even with appropriate biopsy, may require exclusion of other disorders. Unlike Langerhans cell histiocytosis lesions, those of polyostotic sclerosing histiocytosis do not stain positive for S100 proteins or group 1 CD1a glycoproteins and do not reveal Birbeck granules under electron microscopic examination. Infiltration of tissues with lipid-laden macrophages, multinucleated giant cells, lymphocytes, and histiocytes is seen, with the histiocytes staining positive with CD68, CD163, and factor XIIIa and negative with CD1a.

The X-chromosome inactivation pattern of the human androgen receptor gene (HUMARA) assay can assess clonality and has been used in a variety of tumors, including those of Langerhans cell histiocytosis and polyostotic sclerosing histiocytosis. This assay, however, is effective only if monoclonal cells make up more than 20% of the total tumor cell population. (In a study of five cases of polyostotic sclerosing histiocytosis, histiocytes were monoclonal in three cases, polyclonal in one, and homozygous in one.) Investigation of CNS involvement and genetic mutations, including in NRAS and BRAF-V600E, should be performed. [191, 192, 230, 231, 49, 232] Consensus guidelines for the diagnosis and clinical management of this disease are available. [230]

Evaluation of the extent of the disease must be performed, having significant value. This includes imaging studies such as computed tomography (CT) scanning of the chest and abdomen, bone scanning, skeletal survey, magnetic resonance imaging (MRI) of the head, and positron emission tomography (PET) scanning, as well as biopsy and special staining with CD68, CD1a, and S100; chromosome studies (BRAF gene mutation, RAS/MAPK pathway); evaluation to rule out diabetes insipidus; bone marrow aspiration and biopsy; echocardiography; and liver and renal evaluations.


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