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SEER Inquiry System - Report
Produced: 07/11/2025 10:51 PM
Question 20110061
Inquiry Details
References:
Subject matter expert
Question:
Primary site/Histology--Heme & Lymphoid Neoplasms: Should the primary site and histology codes be updated when a patient with a history in 2005 of a bone marrow diagnosis of chronic lymphocytic leukemia later presents in 2010 with lymph node biopsy diagnosis of small B-cell lymphocytic leukemia?
Discussion:
Answer:
For cases diagnosed 2010 and forward, access the Hematopoietic Database at http://seer.cancer.gov/seertools/hemelymph.
Per Rule M2, this is a single primary because there is a single histology. Code histology to 9823/3 [CLL/SLL]/
The distinction of CLL vs. SLL cannot be made on bone marrow biopsy in isolation. The pathologist cannot make a diagnosis of CLL vs SLL without having peripheral blood counts available for review. If the patient was treated for CLL in the past, that may alter the peripheral counts seen in 2010 (e.g., lymphocytosis). The distinguishing feature is peripheral lymphocytosis in CLL (not seen in SLL). The disease looks the same and both will often have bone marrow involvement and lymph node involvement. If the patient had true CLL in 2005, then any subsequent lymph node (or other) biopsy consistent with CLL/SLL remains consistent with the original diagnosis of CLL. I would not change the original CLL code.
I agree with the previous response. We have to assume the 2005 diagnosis included a peripheral blood supporting that diagnosis. Otherwise, CLL and SLL look the same in nodes and marrow. The interplay between the two "diseases" is expected. This is why they are considered a single disease.
SEER*Educate provides training on how to use the Heme Manual and DB. If you are unsure how to arrive at the answer in this SINQ question, refer to SEER*Educate to practice coding hematopoietic and lymphoid neoplasms. Review the step-by-step instructions provided for each case scenario to learn how to use the application and manual to arrive at the answer provided. https://educate.fhcrc.org/LandingPage.aspx.
