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.
Lymph nodes (C770-C779) are the usual primary sites; however, involvement in other sites is possible. If you have confirmation that the only involved site is something other than the lymph nodes, than code to that primary site. See Module 7.
Synchronous OR metachronous occurrence of HL with NHL. Possible explanations:
1) Both arise coincidentally from unrelated lymphoidelements
2) HL progresses from previous NHL
3) Both derive from common precursor cell