Endocrinology and Metabolism Clinics of North America
Thyroid Nodules and Cancers in Children
Section snippets
Environment
A strong association exists between radiation exposure and the development of thyroid cancers. During the first half of the 20th Century, when radiation treatment was used in the treatment of benign conditions such as thymic enlargement of infancy, tonsillar and adenoidal infections, and tinea capitis, Duffy and Fitzgerald [7] reported that 36% of the pediatric patients diagnosed with thyroid cancer were exposed to radiation treatment earlier in life. After discontinuing radiation for these
Pathology
Thyroid cancer types are classified as tumors derived from the thyroid follicle (papillary, follicular, and insular), those derived from calcitonin-producing cells (medullary), and undifferentiated carcinomas (Fig. 1). In addition, insular thyroid carcinoma is less well differentiated than are follicular and papillary carcinomas. Undifferentiated or anaplastic thyroid carcinomas are almost unheard of in children.
Papillary thyroid carcinomas (PTC), follicular thyroid carcinomas (FTC), and
Pathogenesis
As with other cancers, the tumorigenesis of thyroid carcinomas can be explained mainly by two mechanisms: activation of proto-oncogenes (Fig. 4) and inactivation of tumor suppressor genes. The proto-oncogenes include the RET gene in PTC and MTC. Tumor suppressor genes include p53 in FTC and PTEN in FTC and others. The overexpression of angiogenesis stimulators such as vascular endothelial growth factor C in papillary carcinomas and the underexpresion of angiogenesis inhibitors such as
Clinical presentation
Thyroid cancer presents as a painless or tender thyroid mass in 88% to 91% of patients and as painless palpable cervical lymphadenopathy in 14% to 29% of patients [36], [37]. Physical findings that suggest malignancy are hardness of the thyroid nodule and fixation of the nodule to surrounding tissues. Physical findings of the syndromes described above also should be sought. Local tenderness may be caused by hemorrhage inside a solid tumor or by cyst formation.
In the study of 15 children with
Diagnosis
The differential diagnosis of a thyroid nodule includes congenital abnormalities such as thyroid hemiagenesis, abscess, lymphocytic thyroiditis, nodular goiter, cyst, adenoma, and malignancies. A detailed history and family history should be obtained, especially of thyroid disorders and radiation exposure. A family history also should include questions about other components of MEN 2. Patients should be examined for physical findings seen in the syndromes associated with a higher risk of
Treatment
Once FNA cytology or biopsy establishes the diagnosis of thyroid cancer, the best surgical procedure for follicular-cell-derived thyroid carcinomas is either total thyroidectomy or near-total thyroidectomy (total on the side of the lesion and subtotal contralaterally). These procedures have advantages over less aggressive surgeries. Total thyroidectomy can be performed safely in experienced hands and with low complication rates. Thyroidectomy complications include permanent or transient
References (50)
- et al.
Thyroid pathologic findings in patients with Cowden disease
Ann Diagn Pathol
(1999) Papillary thyroid carcinoma: etiology, assessment, and therapy
Endocrinol Metab Clin North Am
(1995)- et al.
Insular carcinoma of the thyroid in a 10-year-old child
J Pediatr Surg
(2003) - et al.
Management of thyroid nodules in children: a 20-year experience
J Pediatr Surg
(1987) The thyroid nodule
- et al.
Structural changes in the thyroid glands of healthy young men
Med Ann Dist Columbia
(1965) - et al.
Thyroid nodules in children: current profile of a changing disease
South Med J
(1989) - et al.
Thyroid carcinoma in children and adolescents
Arch Otolaryngol Head Neck Surg
(1995) - Harach HR, Williams ED. Childhood thyroid cancer in England and Wales. Br J Cancer...
Thyroid tumors