It's All in Your Head

Resection of superficial lesion was performed on 11/29/11. Immunohistochemical examination found lipid laden histiocytes equivocal for S100, positive for CD68 and CD163 arranged in sheets of inflammation with collagen deposition. The large histiocytic cells were CD1a negative and Factor XIIIa positive. Touton giant cells were identified without evidence of emperipolesis. Microbial DNA PCR was negative. No acid fast bacilli, mycobacterium tuberculosis complex or Mycobacterium avium complex DNA were detected. There were no non-caseating sarcoidal granulomas. Pathology consultation from UCSF felt the histiocyte population was S-100 positive, however, NIH/NCI did not. Nonetheless, both agreed that pathology was consistent with Erdheim-Chester disease (ECD). Search for extra-cranial involvement included CT of chest and abdomen, trans-thoracic echocardiogram, long bone x-rays and whole body PET scan, which were unremarkable. Surveillance MRI January and May 2012 found decreasing size of enhancing intracranial lesions without treatment. Repeat visual fields have remained stable and neurologic examination found improved left lower extremity strength. ECD is a non-Langerhans cell histiocytosis (NLCH) proliferative disorder characterized by infiltration of various tissues by foamy histiocytes surrounded by fibrosis of unknown etiology. 1,2 There is a strong male predominance and a mean age at diagnosis of 55 yrs. 1 Osteosclerosis of the long bones with pain is common. Other organs involved are skin, lungs, heart, and kidneys. Retroperitoneal and orbital lesions reported. 2 Central nervous system (CNS) involvement can be seen in up to 50% of affected patients.1 Immunohistochemistry is necessary to differentiate from other NLCH. Presentation typically consists of cerebellar and pyramidal syndromes. 2 CNS MR imaging has revealed intra and extra-axial lesions, including ependymal enhancement, brainstem lesions, thickening of the pituitary stalk, cavernous sinus, sellar and hypothalamic lesions. 3 Treatment is controversial and has included high dose interferon alpha, steroids, biphosphonates, and cytotoxic agents with variable results. 4 Isolated intracranial ECD has been reported twice previously.