TSC1 and skin neoplasm: As we previously determined that dermal but not epidermal TSC2 loss occurs in human TSC skin samples (Li et al., 2008), we hypothesized that conditional disruption of mouse Tsc2 in mesenchymal cells including dermal cells of the skin would be sufficient to induce highly vascular skin tumor formation and produce a source of Tsc2-deficient cells that could be used to discover factors that contribute to TSC tumorigenesis or have potential as diagnostic or prognostic markers of disease.