LAUSR

Dear Editor I read the article entitled BPandora’s box: eosinophilic granuloma at the cerebellopontine angle-should we open it?^ by Öğrenci A et al. [1], with great interest. The authors presented a rare location for presentation of intracranial eosinophilic granuloma (EG). Their patient was found to have a lesion at CP angle showing hypo-intensity on T1and hyper-intensity on T2-weighted magnetic resonance images. They claimed that dramatic response to steroid therapy was so evident that it may obviate the need for a histologic diagnosis and delayed manifestations on patient’s skin and eye, also recovered after a course of corticosteroid therapy. We had a similar adult patient which made us perform a literature review about the management of this rare entity. There are a few concerns that have to be addressed. First, the presentation with skin and eye manifestations shows the erroneous usage of the term EG. EG is referred to the focal form of Langerhans cell histiocytosis (LCH), which primarily involves bones, particularly skull, pelvis, spine, and ribs. Langerhans cell histiocytosis (LCH) is a group of disorders described as neoplastic proliferation of eosinophils, multinucleated giant cells, mononuclear cells, and Langerhans cells. This clinical entity is comprised of three clinical syndromes: Eosinophilic granuloma (EG), HandSchüller-Christian disease, and Letterer-Siwe disease [2]. So the multifocal presentation is against the diagnosis of EG and shows that another multifocal and systemic counterpart of LCH was the correct diagnosis. Second, is a critic of the approach they recommended, steroid therapy before confirmation of histologic diagnosis. Unresponsiveness to steroid therapy may delay the timely management of intracranial lesions, especially at CP angle which is a narrow corridor containing multiple cranial nerves and antero-lateral aspect of the brain stem. Confirming the pathology with surgical, endoscopic, or stereotactic biopsy seems to be a more rational approach. We proposed a management protocol according to the possibility of unresponsiveness to steroids (Fig. 1). Third concern is an interesting imaging finding that arise from the comparison of the presented case by Öğrenci A et al. [1] with our experience. Our adult case of EG at left CP angle, demonstrated hypo-intensity on T2-weighted images (Fig. 2).