The added value of undiluted vitreous biopsy samples processed by the Cellient® tissue processor (Hologic) in unsolved uveitis

Abstract

PurposeIn this prospective study, the added value of undiluted vitreous biopsy samples in the diagnosis of unsolved uveitis was evaluated. 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 challenging cases to differentiate uveitis from lymphoma or infection and to define the type of cellular reaction.Methods97 consecutive undiluted vitreous samples were isolated in patients with unsolved intermediate or posterior uveitis. A 1.5‐2.5cc sample was taken through a single 23G or 27G port using the EVA vitrectomy platform (DORC) with a twin duty cycle high speed cutter. The samples were analysed 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. Routine histochemical and immunostainings were evaluated.ResultsIn 94.8% of the cases, sufficient material was found to provide an added value in the diagnostic workup. In 34%, a Cytolyt® mucolytic wash was necessary to prevent clotting of the tubes in the Cellient® tissue processor due to the viscosity of the sample. In 7% the diagnosis was an acute inflammation (presence of granulocytes), in 42% chronic active inflammation (presence of T‐lymphocytes), in 36% low‐grade inflammation (presence of CD68 cells, with <5% T‐lymphocytes); and in 9% a malignant process (lymphoma). In 5% no diagnosis was found. In the chronic active inflammation group 39% was a granulomatous inflammatory process.ConclusionsThis standardized protocol for sampling and handling undiluted vitreous biopsies gives a superior result in morphology, number of cells, and possibility of immuno‐histochemical stainings. The diagnosis can be established or confirmed in 94.8% of cases.