Pathogenesis, diagnosis and management of thyroid nodules in children

Abstract

According to the literature thyroid nodules are quite rare in the first two decades of life. However, there are some exceptions, relating to areas with an iodine deficiency or affected by radioactive fallout, where the risk of nodules and carcinomas is increased. Therefore, it is a great challenge for the physician to distinguish between benign and malignant lesions preoperatively, and not only in these areas of greater risk. A careful work-up, comprising the patient's history, clinical examination, laboratory tests, thyroid ultrasound, scintigraphy, fine-needle aspiration biopsy (FNAB) and molecular studies, is mandatory to improve the preoperative diagnosis. The differential diagnosis should also include benign thyroid conditions such as: (i) congenital hypothyroidism due to dyshormonogenesis or ectopy, (ii) thyroid hemiagenesis, (iii) thyroglossal duct cyst, (iv) simple goiter, (v) cystic lesion, (vi) nodular hyperplasia, (vii) follicular adenoma, (viii) Graves' disease and (ix) Hashimoto thyroiditis, all of which can predispose to the development of thyroid nodules. The majority of thyroid carcinomas derive from the follicular cell (papillary, follicular, insular and undifferentiated (or anaplastic) thyroid carcinoma), whereas medullary thyroid carcinoma derives from calcitonin-producing cells. Inherited forms of thyroid cancer may occur, especially in relation to medullary thyroid carcinoma. FNAB is a critical factor in establishing the preoperative diagnosis. However, we should keep in mind the fact that a conventional cytological evaluation can miss the neoplastic nature of a lesion and the employment of immunocytochemical and molecular studies of aspirates from FNAB can give us a more precise diagnosis of neoplasia in thyroid nodules once they are detected.

Malignant and benign thyroid nodules after total body irradiation preceding hematopoietic cell transplantation during childhood

“…This prevalence increases with age, particularly during puberty and adulthood, reaching about 20% in midlife in countries with no marked iodine deficiency (30,33). Thyroid nodules are less common in children than in adults, but the risk of malignancy is much higher in children, with an estimation of 10-25% of thyroid nodules being malignant vs only 5% in adults.…”

“…When ultrasound scans revealed thyroid nodules O8 mm in diameter, depending on the ultrasound characteristics of these nodules (i.e. microcalcifications, hypoechogenicity, irregular margins, and intranodular vascularity), a FNAB was performed (30). Surgery was performed in cases of malignant lesions, noninformative FNAB, or patient preference due to the large size of a benign nodule.…”

Pediatric Thyroid Cancers: An Indian Perspective

“…To begin with, there should be an index of suspicionabout malignancy in pediatric thyroid nodules, since thyroid nodules are 5-fold more likely to be malignant in children (26%) than in adults (5%) [24]. Secondly, pediatric DTC are more likely to have regional lymph node involvement and extrathyroidal extension [7].…”

Latin American Thyroid Society recommendations for the management of thyroid nodules

“…The occurrence of thyroid nodules is uncommon in children and adolescents compared with adults, but when present, carry a higher risk of malignancy (14% to 40% in children compared with 5% in adults) (57)(58)(59)(60).…”