A new and standardized method to sample and analyse vitreous biopsies in unsolved uveitis by the Cellient® automated cell block system

Abstract

AbstractPurpose In this prospective study a universal protocol for sampling and analyzing vitreous material was investigated. Vitreous biopsies are difficult to handle because of the paucity of cells and the gelatinous structure of the vitreous. Histopathological analysis of the vitreous is useful in difficult uveitis cases to differentiate uveitis from lymphoma or infection and to define the type of cellular reaction.Methods After isolation of vitreous content by a single port biopsy or by a standardized 23G vitrectomy, 170 consecutive vitreous samples were analyzed with the Cellient® tissue processor (Hologic). This machine is a fully automated processor starting from a specified container with PreservCyt® (fixative fluid) with cells to paraffin. Cytology was compared with fixatives Cytolyt® (contains a mucolytic agent) and Preservcyt®. Routine histochemical and immunostainings were evaluated.Results In 79 cases (46%) a single port biopsy and in 91 cases (54%) a tree port pars plana vitrectomy was performed. In 94% of the cases, sufficient material was found for establishing the diagnosis. In 18%, a Cytolyt® wash was necessary to prevent clotting of the tubes in the Cellient® due to the viscosity of the sample. In 21% the diagnosis was an acute inflammation (presence of granulocytes), in 32% chronic active inflammation (presence of T‐lymphocytes), in 35% low‐grade inflammation (presence of CD68 cells, without T‐lymphocytes); and in 5% a malignant process. In 9% a granulomatous inflammation was detected, in 5% glial tissue (floaters). In 6% no diagnosis was found.Conclusion A standardized protocol for sampling and handling vitreous biopsies, fixing in PreservCyt® and processing by the Cellient® system gives a superior result in morphology, number of cells, and possibility of immuno‐histochemical stainings. The diagnosis can be established or confirmed in more than 90% of cases.