Gerald J Harris1. 1. Department of Ophthalmology, Section of Orbital and Ophthalmic Plastic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. gjharris@mcw.edu
Abstract
PURPOSE: To explore specialty-related perceptions and treatment strategies in Langerhans cell histiocytosis (LCH) of the orbit. DESIGN: A perspective. METHODS: We reviewed the reported ophthalmic experience with unifocal LCH of the orbit, analyzed current oncologic clinical trial protocols, and provided a brief summary of contemporary knowledge and theory of LCH pathogenesis. RESULTS: Ophthalmic literature indicates that unifocal LCH of the orbit is usually responsive to local intervention. Current international oncologic protocols identify orbital LCH as a "central nervous system-risk" lesion (at risk for delayed-onset diabetes insipidus) and mandate a 6-month course of chemotherapy. Analysis suggests that the latter strategy is based on cases of orbital involvement in multifocal and multisystem disease. The pathologic Langerhans cell continues to define and unite the LCH variants, but cytokine activation of that cell may be an earlier pathogenetic determinant. Despite a common cellular mediator, LCH may be a heterogeneous process, with severity related to varied "upstream" trigger events. CONCLUSION: Treatment perspectives in LCH are influenced by dissimilar patient encounters and varied interpretations of the basic disease process. Pending documentation of linkage between unifocal orbital LCH and diabetes insipidus, we recommend local intervention, with systemic treatment reserved for incomplete response or local reactivation or the appearance of lesions elsewhere. LCH underscores the need for close interaction between specialists with intersecting clinical interests.
PURPOSE: To explore specialty-related perceptions and treatment strategies in Langerhans cell histiocytosis (LCH) of the orbit. DESIGN: A perspective. METHODS: We reviewed the reported ophthalmic experience with unifocal LCH of the orbit, analyzed current oncologic clinical trial protocols, and provided a brief summary of contemporary knowledge and theory of LCH pathogenesis. RESULTS: Ophthalmic literature indicates that unifocal LCH of the orbit is usually responsive to local intervention. Current international oncologic protocols identify orbital LCH as a "central nervous system-risk" lesion (at risk for delayed-onset diabetes insipidus) and mandate a 6-month course of chemotherapy. Analysis suggests that the latter strategy is based on cases of orbital involvement in multifocal and multisystem disease. The pathologic Langerhans cell continues to define and unite the LCH variants, but cytokine activation of that cell may be an earlier pathogenetic determinant. Despite a common cellular mediator, LCH may be a heterogeneous process, with severity related to varied "upstream" trigger events. CONCLUSION: Treatment perspectives in LCH are influenced by dissimilar patient encounters and varied interpretations of the basic disease process. Pending documentation of linkage between unifocal orbital LCH and diabetes insipidus, we recommend local intervention, with systemic treatment reserved for incomplete response or local reactivation or the appearance of lesions elsewhere. LCH underscores the need for close interaction between specialists with intersecting clinical interests.