2026 ICD-10-CM Diagnosis Code D44.0

Neoplasm of uncertain behavior of thyroid gland

ICD-10-CM Code:
D44.0
ICD-10 Code for:
Neoplasm of uncertain behavior of thyroid gland
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

D44.0 is a billable diagnosis code used to specify a medical diagnosis of neoplasm of uncertain behavior of thyroid gland. 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 thyroglossal duct or Neoplasm, neoplastic thyroid (gland) .

Code Classification

  • Neoplasms
    C00–D49
    • Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes
      D37-D48
      • Neoplasm of uncertain behavior of endocrine glands
        D44

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.

  • Neoplasm of thyroglossal duct
  • Neoplasm of uncertain behavior of thyroglossal duct
  • Neoplasm of uncertain behavior of thyroid gland

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.

Neoplasms of unspecified nature or uncertain behavior

CCSR Code: NEO072

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 D44.0 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.

Uncer neo endocrine NEC

ICD-9-CM: 237.4

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

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
  »thyroglossal duct
C73C79.89D09.3D34D44.0D49.7
»Neoplasm, neoplastic
  »thyroid (gland)
C73C79.89D09.3D34D44.0D49.7

Patient Education


Thyroid Diseases

Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods.

Thyroid diseases cause your thyroid to make either too much or too little of the hormones. Some of the different thyroid diseases include:

  • Goiter, an enlargement of the thyroid gland
  • Hyperthyroidism, which happens when your thyroid gland makes more thyroid hormones than your body needs
  • Hypothyroidism, which happens when your thyroid gland does not make enough thyroid hormones
  • Thyroid cancer
  • Thyroid nodules, lumps in the thyroid gland
  • Thyroiditis, swelling of the thyroid

To diagnose thyroid diseases, your health care provider may use a medical history, physical exam, and thyroid tests. In some cases, your provider may also do a biopsy.

Treatment depends on the problem, how severe it is, and what your symptoms are. Possible treatments may include medicines, radioiodine therapy, or thyroid surgery.

Dept. of Health and Human Services Office on Women's Health


[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] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.