AAO-HNSF Primary Care Otolaryngology Handbook

CHAPTER 14

(FNAB). This may be performed with or without ultrasound guidance, depending on the size and location of the lesion. While cytopathologic interpretation has improved, a clear diagnosis for malignancy is not always achieved. Reports, such as “indeterminant,” “suspicious,” or “nondiagnostic,” are frequently tendered to the surgeon or endocrinolo- gist, making the decision for resection more challenging. The recent development of molecular genetic tests has helped further stratify these patients into high and low risk for malignancy. FNAB diagnosis of malignant cells, however, is an obvious indication for surgery, either a total thyroid lobectomy or a total thyroidectomy. Certainly, any evidence of thyroid cancer in the neck nodes is an indication for total thyroidectomy and appropriate neck dissection. Remember that absent any risk factors, there is a high degree of proba- bility that the nodule is benign. If the pathologic interpretation on the FNAB favors a benign histopathology and the patient does not have any other risk factors for thyroid cancer, one can advocate observation. If the lab report is indeterminant or inconclusive, molecular testing or a repeat FNAB with the aid of an ultrasound is necessary to ensure sampling efficiency of the tissue. When multiple nodules are found, the thyroid is classified as a multinodular thyroid or goiter , and only the nodules with the most suspicious features on ultrasound or the domi- nant or largest nodules are biopsied. If a single nodule is determined to be inconclusive by FNAB, FNAB should be repeated. Radionuclide thyroid scans have become less essential to the diagnostic workup of nodules with the development and refinement of ultrasound and fine- There are two essential classifications of thyroid cancer: well differenti- ated and other. The more common forms of thyroid cancer are well differentiated and include papillary and follicular (including the Hürthle cell variant). The “other” category includes less-differentiated forms of thyroid cancer, including medullary and anaplastic. Lymphoma may also arise in the thyroid. Papillary Carcinoma Approximately 80 percent of thyroid cancers are papillary histologically. These may have a follicular component , but any amount of papillary component means the tumor will behave more like a papillary tumor. These tumors can be multifocal in the gland and metastasize to neck lymph nodes. The presence of lymph node masses does not appear to needle aspiration techniques. Forms of Thyroid Cancer

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Primary Care Otolaryngology