2025 ICD-10-CM Diagnosis Code C37
Malignant neoplasm of thymus
- ICD-10-CM Code:
- C37
- ICD-10 Code for:
- Malignant neoplasm of thymus
- Is Billable?
- Yes - Valid for Submission
- Chronic Condition Indicator: [1]
- Chronic
- Code Navigator:
C37 is a billable diagnosis code used to specify a medical diagnosis of malignant neoplasm of thymus. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.
The following anatomical sites found in the Table of Neoplasms reference this diagnosis code given the correct histological behavior: Neoplasm, neoplastic thymus (gland) .
Approximate Synonyms
The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.
- Malignant thymoma
- Malignant tumor of thymus
- Neuroendocrine carcinoma of thymus
- Primary malignant neoplasm of thymus
- Primary malignant thymoma
- Primary small cell neuroendocrine carcinoma of thymus
- Primary thymic carcinoma
- Stage I: Grossly and microscopically encapsulated
- Stage IIa: Microscopic transcapsular invasion
- Stage IIb: Macroscopic capsular invasion into thymic or surrounding fat, or grossly adherent to, but not breaking through, mediastinal pleura or pericardium
- Stage III: Macroscopic invasion of neighboring organs
- Stage IVa: Pleural or pericardial dissemination
- Stage IVb: Hematogenous or lymphatic dissemination
- Thymic epithelial neoplasm stage finding
- Thymic epithelial neoplasm stage finding
- Thymic epithelial neoplasm stage finding
- Thymic epithelial neoplasm stage finding
- Thymic epithelial neoplasm stage finding
- Thymic epithelial neoplasm stage finding
- Thymoma
- Thymoma
- Thymoma
- Thymoma
- Thymoma
- Thymoma
- Thymoma
- Thymoma type A
- Thymoma type AB
- Thymoma type B
- Type C thymoma
Clinical Classification
Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.
They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.
Endocrine system cancers - thymus
CCSR Code: NEO052
Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.
Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Clinical Information
Thymoma
a neoplasm originating from thymic tissue, usually benign, and frequently encapsulated. although it is occasionally invasive, metastases are extremely rare. it consists of any type of thymic epithelial cell as well as lymphocytes that are usually abundant. malignant lymphomas that involve the thymus, e.g., lymphosarcoma, hodgkin's disease (previously termed granulomatous thymoma), should not be regarded as thymoma. (from stedman, 25th ed)
Tabular List of Diseases and Injuries
The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.
Type 1 Excludes
Type 1 ExcludesA type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- malignant carcinoid tumor of the thymus C7A.091
Index to Diseases and Injuries References
The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).
- - Carcinoma (malignant) - See Also: Neoplasm, by site, malignant;
- - thymic - C37
- - Thymoma - See Also: Neoplasm, thymus, by type;
- - malignant - C37
- - metaplastic - C37
- - sclerosing - C37
- - type A - C37
- - type AB - C37
- - type B1 - C37
- - type B2 - C37
- - type B3 - C37
Convert C37 to ICD-9-CM
Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.
Malignant neopl thymus
ICD-9-CM: 164.0
This is a direct match with no additional mapping qualifiers. The absence of a flag generally means the mapping is considered exact or precise. In other words, the ICD-10 code maps cleanly to the ICD-9 code without qualification, approximation, or needing multiple codes.
Table of Neoplasms
This code is referenced in the table of neoplasms by anatomical site. For each site there are six possible code numbers according to whether the neoplasm in question is malignant, benign, in situ, of uncertain behavior, or of unspecified nature. The description of the neoplasm will often indicate which of the six columns is appropriate.
Where such descriptors are not present, the remainder of the Index should be consulted where guidance is given to the appropriate column for each morphological (histological) variety listed. However, the guidance in the Index can be overridden if one of the descriptors mentioned above is present.
Neoplasm, neoplastic | Malignant Primary |
Malignant Secondary |
CaInSitu | Benign | Uncertain Behavior |
Unspecified Behavior |
---|---|---|---|---|---|---|
»Neoplasm, neoplastic »thymus (gland) | C37 | C79.89 | D09.3 | D15.0 | D38.4 | D49.89 |
Patient Education
Thymus Cancer
The thymus is a small organ in your upper chest, under your breastbone. Before birth and during childhood, the thymus helps the body make a type of white blood cell. These cells help protect you from infections.
Cancer of the thymus is rare. You are more likely to get it if you have other diseases such as myasthenia gravis, lupus or rheumatoid arthritis. Sometimes there are no symptoms. Other times, thymus cancer can cause:
- A cough that doesn't go away
- Chest pain
- Trouble breathing
Doctors use a physical exam, imaging tests, and a biopsy to diagnose thymus cancer. The most common treatment is surgery to remove the tumor. Other options include radiation therapy, chemotherapy, and hormone therapy.
NIH: National Cancer Institute
[Learn More in MedlinePlus]
Code History
- FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
- FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
- FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
- FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
- FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
- FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
- FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
- FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
- FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.