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ICD-10 Code D44.0: Neoplasm of uncertain behavior of thyroid gland

D44.0 is a billable ICD-10 diagnosis code used to classify Neoplasm of uncertain behavior of thyroid gland in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

đź“‹Clinical overview

This page concerns a thyroid neoplasm classified as having uncertain behavior. A neoplasm is a growth of tissue; uncertain behavior means its benign or malignant nature cannot be established histologically, by examining the tissue. It is not automatically thyroid cancer or a harmless nodule. The precise pathology wording and clinical findings are needed to understand the diagnosis. This label does not identify a tumor subtype, its hormone activity, its likelihood of recurrence or the treatment required.

When is it used?

  • May be used when a clinician documents neoplasm of uncertain behavior of thyroid gland in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

đź©şClinical context

When commonly used
  • Records documenting a thyroid neoplasm whose behavior is classified as uncertain. The official category is distinct from unspecified behavior, a benign thyroid growth and a confirmed malignant thyroid tumor; do not silently exchange those diagnoses.
  • Some thyroid tumors have tissue features that are difficult to place confidently into benign or malignant groups. Uncertain malignant potential is a pathology concept, not simply a statement that an appointment, ultrasound or laboratory result is still pending.
  • An indeterminate fine-needle sample and a tissue diagnosis of uncertain behavior are not automatically the same finding. The actual report and clinical interpretation matter; D44.0 does not assign a Bethesda or Thy cytology category, NIFTP or a particular follicular tumor subtype.
Common workup
  • Review the exact cytology, surgical pathology and operative reports with the thyroid team. They can explain what tissue was examined, which features remain uncertain and whether specialist pathology review would help; the code alone does not describe invasion, margins or a molecular result.
  • Neck examination and ultrasound provide structural information, while tests such as TSH assess thyroid function. Normal hormone results do not establish benign behavior, and an abnormal hormone result does not by itself prove malignancy.
  • Further sampling, molecular tests or imaging are chosen only where they answer a specific remaining question. Some tissue distinctions require examination of a resected specimen rather than a needle sample. The title does not require repeating a biopsy or undergoing a new operation in every case.
Common management context
  • Agree a plan based on the precise diagnosis, what treatment has already occurred, any remaining thyroid findings and the person's circumstances. Ask the endocrinologist or surgeon to distinguish what is known from what remains uncertain.
  • Further surgery or radioactive iodine is not an automatic consequence of D44.0. Current guidance does not routinely recommend these additional treatments for certain pathologically defined very-low-potential tumors, but this broad code alone does not establish that an individual has one of those tumors.
  • Follow-up should be tailored to the report and clinical situation. Ask which examinations, blood tests or ultrasound checks are useful and when to report a change. Do not borrow a fixed cancer-surveillance schedule or assume that uncertain behavior means no review is needed.
  • If thyroid hormone treatment is already prescribed, follow the agreed plan and discuss changes with the clinician. This code does not establish an underactive or overactive thyroid or require thyroid-suppressing treatment, iodine supplements or a cancer-drug regimen.

🔍Key distinctions

Important notes
  • A growing neck lump, persistent voice change or difficulty swallowing needs clinical review. Difficulty breathing or noisy breathing needs emergency medical help rather than waiting for a routine pathology discussion; a pressure symptom does not itself prove cancer.
  • Uncertain behavior does not mean a particular percentage chance of cancer, inevitable progression, spread or a precancer diagnosis in every case. Neither the risk estimate from an indeterminate needle-sample study nor another person's outcome can be assigned from this code.
  • WHO classifications distinguish certain low-risk thyroid neoplasms from benign tumors and carcinomas. These are specific entities with their own criteria, not a reason to label every D44.0 page NIFTP or to apply one entity's treatment or follow-up to all others.
  • This is a thyroid diagnosis, not a parathyroid neoplasm or proof of an inherited endocrine syndrome. Preserve the original uncertain-behavior classification while clarifying its meaning; do not rewrite it as benign or malignant without the relevant clinical evidence.
Related codes to consider
D44.1Neoplasm of uncertain behavior of adrenal gland
Related uncertain-behavior endocrine-site code for navigation; the thyroid, parathyroid, adrenal and other endocrine structures have different tissue criteria, hormone effects and care plans.
D44.2Neoplasm of uncertain behavior of parathyroid gland
Related uncertain-behavior endocrine-site code for navigation; the thyroid, parathyroid, adrenal and other endocrine structures have different tissue criteria, hormone effects and care plans.
D44.3Neoplasm of uncertain behavior of pituitary gland
Related uncertain-behavior endocrine-site code for navigation; the thyroid, parathyroid, adrenal and other endocrine structures have different tissue criteria, hormone effects and care plans.
D44.4Neoplasm of uncertain behavior of craniopharyngeal duct
Related uncertain-behavior endocrine-site code for navigation; the thyroid, parathyroid, adrenal and other endocrine structures have different tissue criteria, hormone effects and care plans.

Code hierarchy

chapter
2Neoplasms (C00-D49)
block
D37-D48Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes
category
D44Neoplasm of uncertain behavior of endocrine glands
currentD44

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

OncologistGeneral PhysicianEndocrinologist

Coverage-related procedures and services

CPT 81546high
ONCOLOGY (THYROID), MRNA, GENE EXPRESSION ANALYSIS OF 10,196 GENES, UTILIZING FINE NEEDLE ASPIRATE, ALGORITHM REPORTED AS A CATEGORICAL RESULT (EG, BENIGN OR SUSPICIOUS)
Source: CMS coverage guidance
CPT 81479high
UNLISTED MOLECULAR PATHOLOGY PROCEDURE
Source: CMS coverage guidance
CPT 70460high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITH CONTRAST MATERIAL(S)
Source: CMS coverage guidance
CPT 70450high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL
Source: CMS coverage guidance
CPT 70470high
COMPUTED TOMOGRAPHY, HEAD OR BRAIN; WITHOUT CONTRAST MATERIAL, FOLLOWED BY CONTRAST MATERIAL(S) AND FURTHER SECTIONS
Source: CMS coverage guidance
CPT 64417high
INJECTION(S), ANESTHETIC AGENT(S) AND/OR STEROID; AXILLARY NERVE, INCLUDING IMAGING GUIDANCE, WHEN PERFORMED
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
D44.0

Common synonyms

Neoplasm of uncertain behavior of thyroid gland

Frequently asked questions

Code details

CodeD44.0
SystemICD10
Display nameNeoplasm of uncertain behavior of thyroid gland
ChapterNeoplasms (C00-D49)
BlockNeoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.