Is C37 a billable ICD-10-CM code?

Yes. C37 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does C37 sit in the tabular list?

Neoplasms (C00-D49), in the block Malignant neoplasms of respiratory and intrathoracic organs (C30-C39).

What cannot be coded together with C37?

C37 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter.

C37

C37 — Malignant neoplasm of thymus

Billable / specific codeICD-10-CM

C37 is a billable, specific ICD-10-CM code for malignant neoplasm of thymus. It is valid for submission on a claim.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

malignant carcinoid tumor of the thymus (C7A.091)

Other codes that can never be billed with C37

These codes carry an Excludes1 note pointing at C37. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading C37 alone.

C49.3Malignant neoplasm of connective and soft tissue of thorax
C75Malignant neoplasm of other endocrine glands and related structures

Risk adjustment

C37 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

HCC 21 Lymphoma and Other Cancers0.671 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score. Look up the whole chart to see which of its HCCs the hierarchy would zero.

Medicare coverage

C37 is named in 63 Medicare coverage policies — 63 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

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How C37 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to C37.

Carcinoma›thymic
Thymoma›malignant
Thymoma›metaplastic
Thymoma›sclerosing
Thymoma›type A
Thymoma›type AB
Thymoma›type B1
Thymoma›type B2
Thymoma›type B3

Code history

C37 has not changed since FY2024 — no addition, revision or deletion across the FY2024–FY2027 ICD-10-CM releases.

Questions about C37

Is C37 a billable ICD-10-CM code?: Yes. C37 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C37 sit in the tabular list?: Neoplasms (C00-D49), in the block Malignant neoplasms of respiratory and intrathoracic organs (C30-C39).
What cannot be coded together with C37?: C37 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter.