In the forepaws, hamartomatous tumors with vascular anomalies formed that were comparable to angiosarcomas or lymphangiosarcomas reported in Tsc1 or Tsc2 genetic mouse models (Onda et al., 1999; Kwiatkowski et al., 2002; Sun et al., 2015; Leech et al., 2015), but these models lacked the large thickened tortuous arteries with smooth muscle dysplasia and variable fibrosis observed in the larger vessels in Tsc2cKOPrrx1-cre mice. The gene discussed is TSC2; the disease is angiosarcoma.