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266 Thyroid and Parathyroid Glands

The aim of treatment is to maintain the serum T level in the high to nodules in prepubertal children have a higher risk of malignancy. The
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normal range (10–14 μg/dl). Treatment is monitored with the reversal natural history of benign lesions in younger children is unknown, and
of clinical signs, linear growth, and TSH levels. 24 the safety of nonoperative treatment has not been documented. In
The prognosis is good for linear growth and skeletal maturity. children younger than 13 years of age, it is currently recommended that
Intellectual progress depends on the age at which treatment is started, all thyroid nodules be removed. 18
and usually poor after 3 months of age. 24 Thyroid Carcinoma
Acquired hypothyroidism Thyroid carcinoma represents about 3% of all paediatric malignancy in
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Acquired, or juvenile, hypothyroidism is commonly caused by autoim- United States. The peak incidence is between the ages of 10 and 18
mune destruction of the thyroid gland secondary to chronic lymphocyt- years, with a female preponderance of 2:1. Thyroid carcinoma is the
ic thyroiditis (Hashimoto’s disease). Other rarer causes are goitrogens second most common cancer in females aged 15–19 years in the United
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(e.g., iodide cough syrups, antithyroid drugs), ectopic thyroid dysgen- States. The incidence of childhood thyroid malignancy was reported
esis, infiltration of the thyroid gland in storage disorders, and secondary to be decreasing in most parts of the world due to the reduced use of
involvement from pituitary disorders with TSH deficiency or hypotha- radiation to treat benign diseases. Individuals who have been exposed
lamic lesions and TRH deficiency. Onset is usually insidious. There to radiotherapy to the neck have a significantly increased chance of
is slowing of linear growth; there may be changes in personality, cold development of thyroid dysfunction. The incidence has been reported
intolerance, diminished appetite, lethargy, and constipation. Girls may as being up to 64%, increasing with time of irradiation, radiation dose,
have breast development, hypertrophy of labia minora, galactorrhae, and age at time of irradiation. 19
and cystic ovarian enlargement; boys may have testicular enlargement The incidence of thyroid carcinoma in children is low in the African
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without a corresponding development of pubic hair. community, with four cases over 10 years reported in Enugu, Nigeria.
Evaluation Three were adenoma, and the remaining one was papillary carcinoma.
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Low serum T , decreased T resin uptake, and elevated TSH are diag- All the patients were girls younger than 10 years of age. In one report,
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nostic. Skeletal maturation is markedly delayed. There is occasional there was only one case of follicular carcinoma, in a 10-year-old girl
association with a slipped femoral epiphysis. Assays of circulating seen over a 10-year period in Ilorin. 26
thyroid antibodies imply an autoimmune basis for the disease. Low or In Nigeria, about 90% of thyroid carcinomas in children are of
normal TSH may suggest hypopituitary or a hypothalamic lesion. A the well-differentiated type: 70% papillary and 20% follicular. The
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TRH stimulation test may be useful in this situation. undifferentiated type, such as medullary carcinoma, is rare. Data from
Treatment the United States, collected retrospectively for the period from 1973
Thyroid hormone replacement with L thyroxin, 3-5 μg/kg as a single to 2004, reported 1,753 cases of thyroid carcinoma occurring under
daily oral dose, is given for life. Adequacy of treatment is monitored the age of 20 years. The condition was more common in females than
with measurement of serum T , reversal of clinical symptoms, and males, and mean survival was 30.5 years. Sixty percent of the tumours
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increased linear growth. were papillary, 23% were the follicular variant of papillary, 10% were
Prognosis is good for catch-up growth and skeletal maturation. follicular, and 5% were medullary. Tumours of the medullary subtype
Catch-up is not expected if hypothyroidism develops around the time are often associated with the familial syndrome of multiple endocrine
of puberty, when skeletal maturation is nearly complete. Intellect is neoplasia type 2 (MEN2). Worse predictors of outcome were male sex,
usually not impaired. 24 nonpapillary tumour subtypes, the presence of distant metastases, and
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Hypothyroidism is rarely treated surgically. nonsurgical treatment.
Neoplastic Diseases of the Thyroid Gland Follicular carcinoma has been described in a neonatal
dyshormogenetic hyperplastic goiter. Total thyroidectomy is necessary
Thyroid Nodules in this instance.
A solitary nodule of the thyroid is an uncommon lesion in children. 2,18 Lateral aberrant thyroid tissues, previously thought to be ectopic
This lower incidence may be because fewer children have been exposed thyroid glands, are now known to represent thyroid carcinoma
to irradiation. It may represent an area of functional hyperplasia (ade- secondary to the cervical lymph nodes. 2
noma), which can be associated with secondary hyperthyroidism. Other Thyroid carcinoma is usually first seen clinically as a thyroid mass,
possible causes of thyroid nodules include: sometimes with an enlarged cervical lymph node. The most common
• adenoma; presentation in childhood is indolent, palpable lymph glands in the
lateral side of the neck. Solitary or multiple nodules in the thyroid
• thyroglossal duct remnant;
glands are usually secondary. The cancer is usually more advanced at
• cystic hygroma; presentation in children when compared to adults, and regional lymph
node metastases are present in 75% of children when the disease is
• germ cell tumour; and
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first detected.
• infected thyroid cyst.
Evaluation
Thyroid nodules are twice as common in girls than in boys. Pathologic diagnosis can be made by either FNA or frozen-section
Most patients present with an asymptomatic anterior neck mass. A biopsy at operation. Most surgeons, however, recommend surgical
thyroid nodule may be a slowly growing, potentially curable, papillary resection of all thyroid lesions due to concern over false negative inter-
2
carcinoma. This is frequently clinically indistinguishable from benign pretation of FNA. 18
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lesions, although the former demonstrates a reduced uptake of iodine I. The functional status of the mass is determined by preoperative
Thyroid imaging studies are unreliable in distinguishing benign scintiscan. A preoperative chest radiograph is necessary because of the
from malignant nodules, but ultrasound may reveal multiple nodules. high incidence of pulmonary metastases in children.
One report has documented an 18% malignant rate by FNA of thyroid Burkitt lymphoma of the thyroid gland has also been reported in
nodules in children. the tropics. 2
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Surgical resection of a thyroid nodule should be performed if it Treatment
is malignant, of indeterminate cytology, is a benign nodule that is
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increasing in size, or is an aspirated thyroid cyst that recurred. Thyroid Surgical excision is the treatment of choice with or without lymph node
dissection.