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ICD-10-CM 2027

ICD-10 code for Metaplastic thymoma

C37

Malignant neoplasm of thymus

✓ Billable / specificCC — complication/comorbidity

From the official ICD-10-CM alphabetic index entry “Thymoma › metaplastic”. Page updated September 29, 2026.

About coding Metaplastic thymoma

The ICD-10-CM code for Metaplastic thymoma is C37 (Malignant neoplasm of thymus).

Don't report C37 together with the conditions in its Excludes1 note: malignant carcinoid tumor of the thymus (C7A.091).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 826 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCC, relative weight 4.7581), DRG 827 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CC, relative weight 2.3896), DRG 828 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCC, relative weight 1.6955), DRG 829 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures with CC/MCC, relative weight 3.1281), DRG 830 (Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Other Procedures without CC/MCC, relative weight 1.4859), DRG 843 (Other Myeloproliferative Disorders or Poorly Differentiated Neoplastic Diagnoses with MCC, relative weight 1.9453) and 2 more, in MDC 17 (Myeloproliferative Diseases and Disorders, Poorly Differentiated Neoplasms), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

Don't confuse with (Excludes1 for C37)

  • malignant carcinoid tumor of the thymus (C7A.091)

Common questions about Metaplastic thymoma ICD-10 codes

What is the ICD-10 code for Metaplastic thymoma?

C37 — Malignant neoplasm of thymus.

Is C37 billable?

Yes. C37 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can C37 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict C37 as a principal diagnosis.

Is C37 a CC or MCC?

C37 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.