ICD 10 Coding Alert

Question: How would you code marginal zone lymphoma (MZL) with spleen involvement? My co-worker thinks it should be C88.4, but I think it should a code from the C83 category. Which of us is right?>

AAPC Forum Participant>

Answer: The confusion here stems from the fact that both codes describe different subtypes of MZL. Clinically, mucosa-associated lymphoid tissue (MALT) lymphoma, also known as extranodal marginal zone lymphoma (EMZL), is distinct from the other types of MZL: splenic marginal zone lymphoma (SMZL) and nodal marginal zone lymphoma (NMZL). Each one has different diagnostic and genetic features, different behaviors, and different treatments (see https://www.ncbi.nlm.nih.gov/books/NBK563276/).

You would code EMZL with C88.4 (Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma]), as the descriptor implies. But SMZL is listed as an inclusion term for the C83.0- (Small cell B-cell lymphoma) code group as you point out, making C83.07 (Small cell B-cell lymphoma, spleen) the correct choice for marginal zone lymphoma with spleen involvement.