ICD-10 Code D44.0 – Neoplasm of uncertain behavior of thyroid gland (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D44.0 – Neoplasm of uncertain behavior of thyroid gland
What it is
D44.0 identifies a thyroid gland neoplasm whose behavior cannot be determined as clearly benign or malignant from available information. Use it when the record documents uncertain behavior of the thyroid.
Clinical signs
Clinical features vary; refer to documentation. Patients may have a thyroid nodule or mass found on exam or imaging, but the code is based on the documented uncertain nature of the lesion, not on symptoms alone.
When to use this code
Use D44.0 when the provider states “uncertain behavior” for a thyroid neoplasm, or when pathology and clinical documentation support that wording. It is appropriate for thyroid lesions described as borderline, indeterminate, or of uncertain malignant potential if the record uses that concept. Check documentation for the exact site and behavior.
Do not use for
Do not use this code for clearly benign thyroid nodules or for confirmed thyroid cancer. If the documentation does not support uncertain behavior, choose the more specific diagnosis documented.
Coding tip
Code from the provider’s stated behavior and site wording; if the thyroid lesion is described only as a nodule, verify whether uncertain behavior is actually documented.