Cyst of thyroid

This code signifies the presence of a fluid-filled sac or lesion within the thyroid gland. These cysts are typically benign and can be solitary or multiple, often discovered incidentally during imaging studies or physical examination.

Apply this code when documentation explicitly states a diagnosis of a thyroid cyst, without further specification of malignancy or other specific thyroid conditions. Supporting documentation would include imaging reports (ultrasound, CT, MRI) describing a cystic lesion of the thyroid, or physician notes confirming the diagnosis.

• Do not use this code if the cyst is identified as malignant; instead, refer to appropriate neoplasm codes.
• If the cyst is associated with hyperthyroidism or hypothyroidism, code the underlying thyroid dysfunction first, then this code as a secondary diagnosis.
• Ensure the documentation clearly differentiates a simple cyst from other thyroid nodules or masses that may require different coding.