#1: Multiple primaries
#2: Heme & Lymphoid Neoplasms
Source 1: Heme & Lymphoid Manual and Database
Notes: September 2020; Effective with Cases Diagnosed 1/1/2010 and Forward
Multiple primaries/Heme & Lymphoid Neoplasms--Lymphoma: Is a 2021 right tongue base biopsy showing diffuse large B-cell lymphoma (DLBCL) (9680/3) a new primary following a prior history of hairy cell leukemia-variant (HCL-v) (9591/3) in 2011? See discussion.
Patient was diagnosed with low-grade non-Hodgkin lymphoma in 2011, later classified as hairy cell leukemia-variant.
Right cervical node biopsy in 2020 proved HCL-v and a subsequent 2021 right tongue base biopsy showed DLBCL. The tongue base biopsy path includes the comment, patient has history of HCL-v, but the morphology and flow cytology features are different from the patient’s previous right cervical node biopsy. This DLBCL likely represents a second de novo lymphoma, but cannot exclude an unusual transformation of the prior HCL-v.
Per Heme Rule M7, abstract a single primary when a more specific histology is diagnosed after an NOS if the Heme DB confirms the same primary. The histology code for HCL-v, 9591/3 is a non-specific code, but it seems like a specific histology. The Heme Calculator does say 9591 and 9680 are the same primary, but we are unsure if that is correct for this case of HCL-v followed by DLBCL.
Abstract two primaries. This is a transformation from a chronic disease (the Hairy Cell Variant) to an acute disease (DLBCL). Although this rare situation is not clearly covered in the Hematopoietic rules, the fact that this was originally a Hairy Cell Leukemia variant means that the DLBCL is a new primary.