2026 ICD-10-CM Diagnosis Code C55
Malignant neoplasm of uterus, part unspecified
- ICD-10-CM Code:
- C55
- ICD-10 Code for:
- Malignant neoplasm of uterus, part unspecified
- Is Billable?
- Yes - Valid for Submission
- Chronic Condition Indicator: [1]
- Chronic
- Code Navigator:
C55 is a billable diagnosis code used to specify a medical diagnosis of malignant neoplasm of uterus, part unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.
The following anatomical sites found in the Table of Neoplasms reference this diagnosis code given the correct histological behavior: Neoplasm, neoplastic uterus, uteri, uterine .
Unspecified diagnosis codes like C55 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.
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.
- Adenocarcinoma of uterus
- Adenosarcoma of uterus
- Carcinoma of uterus
- Carcinosarcoma of uterus
- Leiomyosarcoma of uterus
- Malignant neoplasm involving left fallopian tube by direct extension from uterus
- Malignant neoplasm involving right fallopian tube by direct extension from uterus
- Malignant neoplasm involving urinary bladder by direct extension from uterus
- Malignant neoplasm of uterus
- Malignant tumor involving an organ by direct extension from uterus
- Malignant tumor involving left ovary by direct extension from uterus
- Malignant tumor involving rectum by direct extension from uterus
- Malignant tumor involving right ovary by direct extension from uterus
- Malignant tumor involving vagina by direct extension from uterus
- Malignant tumor involving vulva by direct extension from uterus
- Primary adenosarcoma of uterus
- Primary carcinosarcoma of uterus
- Primary malignant neoplasm of uterus
- Primary myosarcoma of uterus
- Sarcoma of uterus
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.
Female reproductive system cancers - uterus
CCSR Code: NEO031
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.
Convert C55 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.
Malig neopl uterus NOS
ICD-9-CM: 179
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 »uterus, uteri, uterine | C55 | C79.82 | D07.0 | D26.9 | D39.0 | D49.59 |
Patient Education
Uterine Cancer
What is uterine cancer?
Uterine cancer is a cancer that forms in tissues of the uterus, which is sometimes called the womb. The uterus is the place where a fetus grows during pregnancy.
There are two types of uterine cancer:
- Endometrial cancer is the most common type. This type of cancer begins in the cells lining the uterus, known as the endometrium.
- Uterine sarcoma is a rare, more aggressive cancer that is harder to treat. This type of cancer begins in muscle or other tissues in the uterus.
Who is more likely to develop uterine cancer?
Uterine cancer usually happens after menopause. The cause is unknown. However, some factors and conditions that change the balance of hormones in your body may increase your risk. These can include obesity or metabolic syndrome (a group of risk factors for certain health problems).
Other factors and conditions that may increase your risk for:
Endometrial cancer
- Taking estrogen-only hormone replacement therapy (HRT) after menopause.
- Having type 2 diabetes.
- Starting menstruation at an early age or menopause at a later age.
- Having never been pregnant.
- Taking tamoxifen, a medicine used to prevent or treat breast cancer.
- Having polycystic ovary syndrome.
- Having a mother, sister, or daughter who has had endometrial cancer.
- Having certain genetic conditions, such as Lynch syndrome.
- Having endometrial hyperplasia (thickening of the uterine lining).
Uterine sarcoma
- Having had past treatment with radiation therapy to the pelvis.
- Taking tamoxifen, a medicine used to prevent or treat breast cancer.
What are the symptoms of uterine cancer?
The most common symptom of both endometrial cancer and uterine sarcoma is abnormal vaginal bleeding. Both types of uterine cancer may also cause pelvic pain or pressure, unusual vaginal discharge, or an enlarged uterus or pelvic mass.
Less common symptoms may include urinating (peeing) often, having trouble urinating, or pain during sexual intercourse.
How is uterine cancer diagnosed?
If you have symptoms of uterine cancer, your health care provider may:
- Ask about your medical history and family health history.
- Do a pelvic exam.
- Order imaging tests.
- Suggest a biopsy or a minor procedure called dilation and curettage (D & C) to check the lining of your uterus.
What are the treatments for uterine cancer?
Treatment may depend on your health, how much cancer you have, and whether it has spread. The most common treatment is having a hysterectomy, which is surgery to remove the uterus. Sometimes the surgery also removes the ovaries and fallopian tubes.
You may have more than one type of treatment. Other treatments may include:
- Hormone therapy
- Radiation therapy
- Chemotherapy
Can uterine cancer be prevented?
There is no sure way to prevent uterine cancer. But you can do things that may help lower your risk such as aiming for a healthy weight, getting regular physical activity, and talking to your provider about the benefits and risks of hormone therapy.
NIH: National Cancer Institute
[Learn More in MedlinePlus]
Endometrial Cancer Treatment (PDQ®)
Learn about endometrial cancer risk factors, signs and symptoms, tests to diagnose, factors affecting prognosis, staging, and treatment.[Learn More in MedlinePlus]
Code History
- FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
- FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
- 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.