SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.
Predominantly extranodal, characterized by a broad morphologic spectrum. The infiltrate is often angiocentric, with prominent necrosis and vascular destruction. It is designated NK/T (rather than NK) because while most cases appear to be NK cellneoplasms, (EBV+ CD56+), rare cases show EBV+ CD56- cytotoxic T-cellphenotype.