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C90.21 vs Z85.79

C90.21 (Extramedullary plasmacytoma in remission) compared with Z85.79 (Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.

Can these codes be reported together?

No — do not report together. C90.21 carries an Excludes1 note covering Z85.79: “personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues (Z85.79)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

No — do not report together. Z85.79 carries an Excludes1 note covering C90.21: “plasmacytoma in remission (C90.21)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Side by side

C90.21Extramedullary plasmacytoma in remissionZ85.79Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues
Billing statusBillableBillable
ClassificationC00-D49 — Neoplasms (C00-D49)Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)
DefinitionExtramedullary plasmacytoma in remission is a billable ICD-10-CM diagnosis code (C90.21).Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues is a billable ICD-10-CM diagnosis code (Z85.79).
Includes
Conditions classifiable to C88-C90, C96
Use additional code
code to identify:
alcohol use and dependence (F10.-)
exposure to environmental tobacco smoke (Z77.22)
Code first
any follow-up examination after treatment of malignant neoplasm (Z08)

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources