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SEER Inquiry System - Report
Produced: 08/01/2025 4:42 PM
Question 20240071
Inquiry Details
References:
#1: Heme & Lymph Manual & DB. Published August 2021
#2: Journal article. https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00555-2/fulltext
Question:
Heme and Lymphoid Neoplasms/Multiple Primaries--Myeloproliferative Neoplasms: Are essential thrombocytosis (ET) in 1998 and primary myelofibrosis in 2022 the same primary or is the 2022 diagnosis a new primary? See Discussion.
Discussion:
Patient was diagnosed with essential thrombocytosis 9962/1 or 3 in 1998 (depending if ET was reportable in 1998), treated with Hydrea.
11-17-2022 Blood smear: CALR + myeloproliferative neoplasm, Most Consistent with Primary Myelofibrosis 9961/3 (Noted CALR and ASXL1 mutations).
The following abstractor note from 9661/3 is confusing: A diagnosis of "post essential thrombocythemia myelofibrosis" is a progression of essential thrombocythemia and would be the same primary.
Answer:
Abstract two separate primaries, ET (9962/3) and primary myelofibrosis (9961/3) using the current Hematopoietic and Lymphoid Neoplasms (Heme) Manual and Database (DB), Rule M15, use the Heme DB Multiple Primaries Calculator. Also refer to the example in Rule M15. In 1998, though the ET was not reportable (9962/1), the patient was treated with chemotherapy as a malignant neoplasm (9962/3). The Calculator instructs us to code separate primaries for these two histologies.
ET may evolve into a secondary myelofibrosis, also known as post-essential thrombocythemia-myelofibrosis (post-ET MF). The diagnosis must be stated as post-ET MF; this would be a single primary.
