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Thyroid Cancer

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decision for resection more challenging. An 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 can-

cer in the neck nodes is an indication for total thyroidectomy and appropri-

ate neck dissection.

Remember, that absent any risk factors, there is a high degree of probabil-

ity 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, 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 dominant 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-needle aspiration techniques.

Forms of Thyroid Cancer

There are two essential classifications of thyroid cancer: well differentiated

and other.

The more common forms of thyroid cancer are well differen-

tiated, and include papillary and follicular

(including the

Hürthle cell

variant). The “other” category includes less well-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 com-

ponent means the tumor will behave more like a papillary tumor. These

tumors

can be multifocal

in the gland and

often metastasize

to neck lymph

nodes. The presence of lymph node masses does not appear to affect sur-

vival rates. Histologically, they have

clear nuclei

(“Orphan Annie”

cells

and may have

psammoma

bodies. Factors predictive of a better prognosis

include small size (less than 1.5 centimeters (cm)) and absence of thyroid

gland capsule involvement. For unknown reasons, this disease follows a

much more indolent course when discovered in people under age 40. How-

ever, while papillary carcinoma patients under 40 years of age ultimately live

longer, they also experience a higher rate of recurrence.