Table 1.

2017 Consensus Histologic Criteria

ANNUBP	Neurofibromatous neoplasm with at least 2 of 4 features: cytologic atypia, loss of neurofibroma architecture, hypercellularity, and mitotic index > 1/50 HPFs and <3/10 HPFs
MPNST, low-grade	Features of ANNUBP, but with mitotic index of 3–9/10 HPFs and no necrosis
MPNST, high-grade	MPNST with at least 10 mf/10HPFs or 3–9 mf/10 HPFs combined with necrosis

ANNUBP = atypical neurofibromatous neoplasm of uncertain biologic potential; HPFs = high-power fields; MPNST = malignant peripheral nerve sheath tumors.