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September 2, 2008

Coding for Thyroid Nodules
For The Record
Vol. 20 No. 18 P. 26

Thyroid nodules are abnormal growths or lumps on the butterfly-shaped gland located at the base of the neck that produces metabolism-regulating hormones. The nodules may be solid or fluid filled and benign or malignant.

There may be no signs or symptoms with early-stage malignant thyroid nodules. However, a patient may experience a lump just below the Adam’s apple, hoarseness, difficulty swallowing or breathing, swollen lymph nodes in the neck, pain in the throat or neck, or hyperthyroidism or hypothyroidism symptoms if the cancer grows. These symptoms may also be caused by benign thyroid nodules, infection or inflammation of the thyroid gland, or a goiter.

Types of Thyroid Nodules
Thyroid nodules are classified to ICD-9-CM code 241.0, Nontoxic uninodular goiter. If a nodule is with hyperthyroidism or thyrotoxicosis, assign code 242.1x. A fifth-digit subclassification is needed to identify the presence or absence of thyrotoxic crisis or storm. The following are common types of benign and malignant thyroid nodules:

• Benign neoplasm of the thyroid glands (226).

• Papillary cancer (193) is the most common form of thyroid malignancy, typically developing in the follicle cells of one thyroid lobe. It can be removed completely via surgery with a good prognosis. This type of thyroid cancer commonly metastasizes to the lymph nodes.

• Follicular cancer (193) also develops in the follicle cells and can be completely removed with a good prognosis. Although it is more aggressive than papillary cancer, it does not spread to the lymph nodes but may metastasize to the lungs and bones.

• Medullary cancer (193) develops from the thyroid’s C cells and is more aggressive, harder to treat, and may spread to the lymph nodes or other organs. Blood tests typically show an elevated carcinoembryonic antigen level.

There are three types of medullary cancer: sporadic, familial, and multiple endocrine neoplasia, type II (MEN II), an inherited form with possible tumors in other endocrine glands, such as adrenal or parathyroid. There are two subtypes, MEN Type IIA (258.02) and MEN Type IIB (258.03). According to coding directives, use additional codes to identify malignancies (such as thyroid cancer, 193) and other conditions associated with MEN Type II, along with a code from subcategory 258.0 (AHA Coding Clinic for ICD-9-CM, 2007, fourth quarter, pages 70-72).

• Anaplastic cancer (193) is very aggressive with a poor prognosis. It can spread quickly to the lymph nodes and trachea and sometimes to other organs or bones.

• Thyroid lymphoma starts in the immune system cells called lymphocytes. Some lymphoma starts in the thyroid, not just in the lymph nodes. The specific ICD-9-CM code assignment will depend on the type of lymphoma documented. Primary malignant neoplasms of lymph nodes or glands are classified to categories 200 to 202. If the lymph nodes around the thyroid gland are involved, then the fifth-digit subclassification of “1” will be assigned.

With benign and malignant thyroid neoplasms, coding directives instruct coders to use an additional code to identify any functional activity such as corticoadrenal insufficiency (255.41), hyperthyroidism (242.80 to 242.81), or hypopituitarism (253.2). If a functional activity or condition is documented, it should be coded separately. Sequencing of the thyroid neoplasm with the functional condition will depend on the circumstances of admission. The neoplasm code should be sequenced first unless the functional condition meets the criteria for principal diagnosis.

The most definitive treatment method for thyroid nodules includes surgery. A near-total thyroidectomy may be the procedure of choice, which leaves a small rim of the thyroid tissue around the parathyroid gland to reduce the risk of parathyroid damage. A near-total thyroidectomy is classified to code 06.39, Partial thyroidectomy. If a total thyroidectomy is performed, assign code 06.4.

The excision of lymph nodes around the thyroid (cervical region) defaults to code 40.21, Excision of deep cervical lymph node. However, if the physician states that the lymph node is superficial, assign code 40.29, Simple excision of lymphatic structure. Other treatment methods include thyroid hormone therapy, radioactive iodine (radioiodine)—according to ICD-9-CM coding directives, if a patient is admitted for radioactive iodine therapy, the condition should be sequenced as the principal diagnosis—external beam radiation, and chemotherapy.

Coding and sequencing for thyroid nodules are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to nearly 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.