SDHB and acquired polycythemia vera: In the other 7 patients with MPGL, the evaluation of Ki-67 showed values of 0.1% to 3.7% in 4 patients with iMPGL and 5% to 6.2% in 3 patients with aMPGL, 2 of whom were carriers of PV in SDHB. Therefore, we suggest that in patients with intermediate PSPGL (20 < PSPGL ≤ 39), we should consider other factors for risk prediction such as Ki-67 and the presence of PV in genes that are associated or not with metastatic disease.