ICD-10 Code C88.4 – Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C88.4 – Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma]
What it is
C88.4 identifies a low-grade B-cell lymphoma arising in mucosa-associated lymphoid tissue outside lymph nodes. You use it for MALT lymphoma when the record specifies extranodal marginal zone B-cell lymphoma.
Clinical signs
Clinical features vary; refer to documentation. Commonly, the diagnosis is confirmed by pathology showing extranodal marginal zone B-cell lymphoma involving a mucosal site such as stomach, salivary gland, lung, or orbit.
When to use this code
Use C88.4 when the provider documents MALT lymphoma or extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. It fits confirmed disease at an extranodal site, not just a suspected mass or nonspecific lymphoid infiltrate. Check documentation if the site or histology is unclear.
Do not use for
Do not use C88.4 for nodal marginal zone lymphoma or other non-MALT lymphomas. If the record only says lymphoma, unspecified, or a different subtype, code the documented diagnosis instead.
Coding tip
Confirm both the MALT subtype and the extranodal location in the pathology or oncology note before assigning C88.4.