Abstract
Thank you for your interest in our case report and your comments regarding the histomorphological diagnosis and interpretation of accumulation of cells in the choroid plexus. We wholeheartedly agree that when characterizing atypical or unusual findings of low occurrence, ancillary procedures are very important for verifying the cells/tissue of origin. While not detailed in our case report, we attempted immunohistochemistry using an adipophilin reagent. We had success characterizing adipocytes with this reagent in our mouse and human assays and were hoping we would observe cross reactivity in other species. Unfortunately, we were unable to validate the assay in our laboratory (no staining in the positive control), thus making a definitive interpretation using this specific marker impossible. In addition, we considered Oil-Red-O and Sudan Black B staining as possible courses of action, but this being a retrospective study, we did not have fresh or frozen tissues which made these assays not appropriate to pursue. Based on these impediments and given the young age of these animals, the substantiated report in the rabbit literature of adipocytes in the choroid plexus, and corroborative location and morphology of the cells by multiple reviewers, we believe the diagnosis of normal adipocytes is accurate and important to share with the Toxicologic Pathology readership.
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