Thyroid Cancer ICD-10-CM codes

All primary thyroid malignancies, whether papillary, follicular, medullary, or anaplastic, are coded to the single code C73. Histologic type and laterality are not captured. Metastatic spread is coded in addition: C77.0 for cervical lymph node involvement, C78.0- for lung metastasis, and C79.51 for bone metastasis.

Before pathology is available, a thyroid nodule is E04.1 (nontoxic single nodule) or E04.2 (multinodular goiter). After biopsy, a benign adenoma is D34, and D44.0 (neoplasm of uncertain behavior of thyroid gland) is assigned only when the pathologist states that the behavior cannot be determined, for example a follicular neoplasm awaiting surgical pathology. Do not use D44.0 to mean a nodule that has not yet been biopsied.

After thyroidectomy or radioactive iodine ablation, the resulting hypothyroidism is E89.0 (postprocedural hypothyroidism), not E03.9, and the patient's lifelong levothyroxine is a treatment of that condition rather than of the cancer. When the cancer has been removed with no evidence of disease and no treatment directed at it, report Z85.850 (personal history of malignant neoplasm of thyroid) together with E89.0. If the patient is still on TSH-suppression therapy or surveillance the provider considers active cancer management, C73 continues to apply.