C37Malignant neoplasm of thymus

C37 is the ICD-10-CM diagnosis code for malignant neoplasm of thymus. It belongs to block C30-C39 (malignant neoplasms of respiratory and intrathoracic organs) and chapter 2 (neoplasms). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 164.0 (malignant neoplasm of thymus).