Approach to the Patient with
a Thyroid Nodule
Nodules of the thyroid are quite common in the
United States. It is estimated that between 4-10% of the population will
have a palpable nodule at some point in their lives and the risk appears to be
greater in women than in men. Although nodular disease is common,
malignant disease is rather uncommon (about 12,000 new cases per year or roughly
5% of nodules).
A goiter is simply an enlargement of the thyroid
gland and may be diffuse or nodular. The presence of a goiter does not
necessarily suggest a diagnosis, as many diseases of the thyroid may be
associated with a goiter. For example, a goiter may be present in both
hyper- and hypothyroidism. Worldwide, the most common cause of goiter is
iodine deficiency. This has been largely eliminated in the United States
by the supplementation of iodine in table salt. The majority of goiters
are benign and like their nodular counterparts, they are more common in women
than in men (about 4:1).
Before discussing the different diseases of the
thyroid and the different causes for goiter or a thyroid nodule, it is important
to review the anatomy of the thyroid as well as the physiology of thyroid
hormone synthesis. The anatomy of the thyroid will understate important
surgical considerations and an understanding of thyroid hormone synthesis is
important in appreciating how disease manifests itself when normal physiology
In addition to a
thorough history and physical for a patient presenting with
complaints that arise suspicion of a thyroid disorder, and good
examination of the thyroid gland is always in order. The
gland itself is usually easier to feel in a long slender neck
than in a short, stocky person. The following steps
outline a typical thyroid exam.
In addition, if the
thyroid gland is enlarged, the lateral lobes can be auscultated
with a stethoscope in order to detect bruits, which may be due
to compression of thyroid vessels by a goiter or nodule.
Thyroid disease can
be categorized into benign conditions of the thyroid and
malignant ones, and rarely there can be progression of one to
the other. The most commonly benign conditions affecting
the thyroid gland are those which cause hyper- and
hypothyroidism. Malignancy of the thyroid is usually of
the carcinoma variety.
Factors which favor
benign disease over malignancy include a family history of
autoimmune disease (i.e. Hashimoto's) or benign thyroid nodule
or goiter, the presence of hormonal dysfunction (hyper- or
hypothyroidism), pain or tenderness associated with the nodule,
and a soft, smooth, and mobile nodule.
Factors which favor
malignant disease include age younger than 20 years or older
than 70 years, male sex, history of neck irradiation, firm,
hard, or immobile nodules, cervical lymphadenopathy, and
associated dysphagia or dysphonia.
subcategories are presented below.
A number of
diagnostic modalities exist for the work-up of a thyroid nodule,
goiter, or symptoms of thyroid disease. They range from
the most non-invasive (ultrasound) to the most invasive
(biopsy). Initial work-up typically involves blood tests,
and the favored initial step in the work-up of a thyroid anomaly
is a sensitive Thyroid Stimulating Hormone (TSH) assay. A
link to each of the commonly used investigations is
The treatment of
thyroid disorders depends on the type and extent of disease
present. For example, hypothyroidism and some forms of
hyperthyroidism can be managed medically. Other times,
surgical intervention is necessary, particularly in the case of
malignancy. As this tutorial deals with the surgical
aspect of dealing with thyroid disease, the surgical management
will be presented comprehensively. Medical management will
be briefly mentioned under the specific disease entities where
such therapy is warranted.
In addition, the
staging system for thyroid malignancies will be outlined as
staging is important in guiding treatment decisions (i.e.
surgery vs. chemotherapy) and predicting prognosis.
Thyroid cancer is somewhat unique in that a number of different
systems have been developed to determine staging. Most of them
focus on weighing such factors as a patient's age, the size of a
cancer at the time of diagnosis, whether the cancer has spread
to invade other structures in the neck, and whether the cancer
has metastasized to other sites in the body.
Fortunately, if caught early, thyroid cancer is very treatable
and survival rates are close to 100%.