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 30 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.
Extranodal NK/T celllymphoma almost always shows an extranodal presentation. Some cases may be accompanied by secondary LN involvement although rare instances of primary LN disease in the absence of extranodal involvement has been reported.