Within these schwannomas, the authors demonstrated not only prominent infiltration of arginase-1 expressing M2-type macrophages but also increased expression of numerous cytokines including IL-1, IL-6, and TNF-α within tumor lysates.20 The above-cited studies, however, focus on schwannoma formation in peripheral nerves and as such the applicability of these injury models to VS formation is currently unclear. Here, TNF is linked to neoplasm.