Figure 1.

Hand drawn illustration of patterns and location of perineural invasion. (a) Complete encirclement, intratumoral location (b) complete encirclement (c) incomplete “crescent-like” encirclement, peripheral location (d) sandwiching “onion skin” (e) partial invasion, extratumoral location (f) neural permeation. Abbreviations: PN: Peripheral nerve, TI: Tumor island, MS: Mesenchymal stroma, TM: Tumor mass, IE: Invasive edge, TN: Tumor necrosis, DSM: Degenerating skeletal muscle, AT: Adipose tissue