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La maladie xanthogranulomateuse de l’adulte est une rare hystiocytose à cellule non-Langerhans et mal diagnostiquée qui affecte la région orbitale et les annexes cutanées. Elle est classée en quatre types [le xanthogranulome de l’adulte (AOX), l’asthme de l’adulte et le xanthogranulome périoculaire (AAPOX), le xanthogranulome nécrobiotique (NBX) et la maladie d’Erdheim–Chester (ECD)] avec des aspects pronostiques et thérapeutiques différents. Dans cette communication, nous présentons le cas d’une patiente présentant un xanthogranulome orbital qui avait été auparavant diagnostiqué comme un xanthélasma de la zone péri-oculaire.

AimTo assess a newly developed immunohistochemical detection system, the EnVision^TM+.MethodsA large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision^TM+ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate^TM methods, when applied either manually or in a TechMate 500 immunostainer.ResultsWith the vast majority of the antibodies, EnVision^TM+ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMateTM techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision^TM+ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard.ConclusionsThe EnVision^TM+ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.