langerhans cell histiocytosis of the orbit diagnosed by fine needle aspiration: two case reports

purpose : fine needle aspiration (fna) cytologic findings of langerhans cell histiocytosis (lch) have been well described, but using this method in the diagnosis of orbital lesions is a recent experience. we hereby report two cases of orbital bone lch diagnosed by fna that later was confirmed by routine h&e; histopathology and immunohistochemistry (ihc) methods. case reports : the first case was a one-year-old boy with a left upper lid mass. radiologic findings were suspicious for malignancy. the other case was a three-year-old boy with right lower lid edema. radiographic study revealed a mass with peripheral condensation and orbital bone defect. fna of lesions in both patients showed a mixed cell population of eosinophils, neutrophils and lymphocytes admixed with neoplastic histiocytes with folded nuclei. consequently, the cytological diagnosis was “langerhans cell histiocytosis” that was confirmed by the routine histopathologic examination. in both cases staining for cd1a by ihc method was also performed that showed positive reaction. conclusion : lch should be considered in differential diagnosis of primary orbital bone lesions specially in childhood. fna method may be useful in the diagnosis of orbital lesions suspicious for lch.   iranian journal of ophthalmology 201022(1):56-59 © 2010 by the iranian society of ophthalmology