On IHC, CD56 positivity and a peripheral sustentacular S100 pattern (with Ki-67 30%-40%), together with negativity for CD3, CD20, TIA-1, granzyme B, chromogranin, and synaptophysin, support ENB and argue against NK/T-cell lymphoma (absence of lymphoid/cytotoxic markers) and undifferentiated/neuroendocrine carcinomas (given the neurofibrillary matrix and the sustentacular S100 pattern). Here, NCAM1 is linked to T-cell non-Hodgkin lymphoma.