Thyroid nodules in childhood and their management

Paediatric thyroid cancer: the Scottish experience

BACKGROUND AND AIMS

Paediatric thyroid cancer is a rare disease, making diagnosis and treatment particularly challenging. Here we present the Scottish experience of thyroid cancer in the paediatric population and give an overview of how a child or adolescent that presents with a thyroid nodule should be investigated and managed.

METHODS AND RESULTS

Data has been obtained from ISD Scotland, giving population-based information on paediatric thyroid cancer. A literature review has been performed on the management and treatment of thyroid cancer in the younger population. Paediatric thyroid cancer in Scotland is a rare disease, although the incidence is increasing each year. In general, differentiated paediatric thyroid cancer carries a good prognosis, while the results are more mixed in the rarer pathologies such as medullary cancer.

CONCLUSION

Due to the small numbers of patients diagnosed each year in Scotland, it is imperative that these patients are discussed at a multidisciplinary thyroid MDT and managed in a tertiary referral centre by consultants and medical/nursing support staff who have experience in treating these patients.

Differentiated Pediatric Thyroid Cancer: Correlates With Adult Disease, Controversies in Treatment

The biologic behavior of differentiated thyroid cancer can differ between adults and children, especially in those children younger than 10 years of age. Unlike adults, young children typically present with advanced disease at diagnosis. Despite this, children respond rapidly to therapy and have an excellent prognosis that is significantly better than that of their adult counterparts with advanced disease. In contradistinction to adults, children with thyroid cancer also have higher local and distant disease recurrences with progression-free survival of only 70% at 5 years, mandating life-long surveillance. Although thyroid cancer is the most common carcinoma in children, overall incidence is low, a factor that has prevented performance of a controlled, randomized, prospective study to determine the most efficacious treatment regimen in this age group. So, although extensively investigated, treatment of pediatric patients with differentiated thyroid cancer remains controversial. This article reviews the current controversies in the treatment of pediatric differentiated thyroid cancer, focusing on issues of optimal initial and subsequent therapy as well as that of long-term follow-up. Our approach to treatment is presented. In so doing, similarities and differences between adults and children with differentiated thyroid cancer as regards unique considerations in epidemiology, diagnosis, staging, treatment, therapy-related late effects, and disease surveillance are presented. The expanding use of and appropriate roles for thyrogen and fluorine-18-fluorodeoxyglucose positron emission tomography in disease evaluation and surveillance will be addressed.

Is it useful to routinely biopsy hot nodules in iodine deficient areas?

Incidence of nodular thyroid disease as well as that of functioning thyroid nodules (FTN) increases dramatically in iodine deficient (ID) areas. Cancer is extremely rare in FTN; thus, some do not routinely biopsy and treat them with radioactive iodine (RAI) straight away or follow-up. The outcome of 296 patients followed or treated at our institution for solitary or multiple FTN were retrospectively evaluated. Hospital records of 224 female, 72 male patients, with a mean +/- SD age of 54.9 +/- 12.4 yr and followed for 22 (0-156) months were examined. 175 patients had solitary, 121 had multiple hot or warm nodules. 230 (77.7%) of the patients received RAI treatment. 402 fine needle aspiration biopsies (FNABs) were performed on 260 patients and on 343 FTN (381 benign and 21 suspicious diagnoses). Eleven of the patients were operated for suspicious FNAB results and 10 were followed-up. Only one nodule turned out to be malignant. Malignancy is extremely rare in functioning thyroid nodules (0.34%) and some of malignant cases could be predicted by their suspicious clinical features. Routine practice of treating FTN with RAI therapy is reasonable in clinically low-risk patients. FNAB is reserved for cases with suspicious clinical features, resulting in fewer surgeries and reduced cost.

Thyrotoxicosis in children

Graves' disease is the predominant cause of hyperthyroidism in the pediatric age group. Other disorders must be recognized, however, because adequate management relies on a precise diagnosis. Careful monitoring of the thyroid status is required during this active phase of growth and development.

Hürthle cell carcinoma in an autonomous thyroid nodule in an adolescent

A 16-year-old girl presented with a palpable thyroid nodule which was found to be functioning autonomously by radioiodine (123I) scintigraphy. After needle biopsy proved non-diagnostic, surgical excision showed the nodule to be Hürthle cell carcinoma. Functional thyroid nodules are rarely malignant, thyroid carcinoma is rare in childhood, and Hürthle cell carcinoma is a rare thyroid neoplasm, so the presence of these three rare conditions in one patient makes it a very unusual case.

Nodular thyroid disease and thyroid carcinoma

The primary challenge in the management of a solitary nodule of the thyroid or a multinodular thyroid gland is to rule out a malignancy.

Management of thyroid nodules in children: a 20-year experience

The medical records and surgical slides of 58 patients with the diagnosis of thyroid nodules (solitary nodule in 50 patients) are reviewed. The most common cause of thyroid nodules in this series is follicular adenoma (27 patients or 46%). A nuclear scan (technetium or radioactive iodine) was performed in 55 patients, of which 40 showed a cold nodule. Twelve of the 40 cold nodules were malignant (30%). However, for solitary nodules the incidence of cancer is 27%. This last figure is significantly greater than the one recently reported by Hung et al (18.5%). Available diagnostic methods are reviewed and the clinical management as derived from our experience is presented.

Differential diagnosis of goiter

Goiters can be detected in about 5 per cent of school-aged children. Goiters appearing during childhood are the result of distinct diseases and should be investigated rather than attributed to "physiologic hyperplasia." The etiology of the diffuse goiter can often be established by clinical evaluation, performing thyroid function tests, and measurement of serum thyroid antibodies. Unlike diffuse goiters, thyroid nodules frequently require tissue examination to exclude malignancy. The goal in evaluating children with nodular goiters is to be as selective as possible in submitting children to surgery without missing cases of cancer. The decision to perform an open biopsy should be based on detecting increased risk for cancer in the medical history, physical examination, or laboratory tests as outlined in Figure 1. Ultrasonography and fine-needle aspiration of nodules are two new methods that aid in the selection of patients for surgery or a trial of thyroid hormone suppression.

Thyroid nodules in children

Thyroid nodules are infrequently encountered in children. During the era of low-dose therapeutic irradiation, the incidence of malignancy in these lesions was 40% to 70%. Recent studies suggest that this incidence is declining, resulting in a concomitant relative increase in the proportion of benign nodular conditions. There is also a heightened awareness that secondary thyroid neoplasms may occur in children surviving primary malignant diseases. Records of 38 children treated surgically at Texas Children's Hospital between 1972 and 1984 have been reviewed to determine the incidence of benign vs. malignant pathosis and to study the role of prior irradiation or chemotherapy in the pathogenesis of thyroid disease. Benign conditions were diagnosed in 27 children (71%), with diffuse hyperplasia (10 children, 26%) and follicular adenoma (8 children, 21%) occurring most frequently. Thyroid carcinoma was diagnosed in the remaining 11 children (29%). All of these patients were euthyroid at presentation, none had received multimodal therapy for a prior malignant condition, and only one had a history of head and neck irradiation in infancy for a treatment of a benign condition (a congenital hemangioma). The clinical presentation, diagnostic evaluation, and surgical management of these patients are reviewed and closely parallel those of patients in other recently published series. No conclusions can be drawn regarding the development of thyroid neoplasia following multimodal therapy for primary disease; however, this incidence must be very low.

Hyperfunctioning thyroid nodules in children and adolescents

Eight children and adolescents, seven female and one male, aged 7.1 to 15.0 years, referred over a 12-year period for a solitary mass in an otherwise normal thyroid gland, exhibited a hyperfunctioning nodule on thyroid scintiscan. Tracer uptake in the surrounding thyroid tissue was reduced or completely suppressed, but could be restored after TSH stimulation. Only one patient had mild clinical hyperthyroidism with normal T4 but increased T3 serum levels and blunted TSH responsiveness to TRH. A similar hormonal pattern suggestive of subclinical hyperthyroidism was found in three other subjects who were clinically euthyroid. One patient initially euthyroid progressed to subclinical hyperthyroidism two years later. In the whole group a significant negative relationship was found between serum T3 level and TRH-stimulated TSH peak (r = -0.829, p less than 0.02). All the patients underwent selective surgery after a 3-month to 2-year period of follow-up. Microscopic examination was consistent with adenoma in seven patients, while in one case a well-encapsulated papillary adenocarcinoma was found. Though hyperfunctioning nodules are seldom malignant, their surgical removal must be recommended when they become thyrotoxic, exceed 3 cm or show progressive enlargement.

Endocrine disorders in children

The childhood endocrine disorders in which surgical intervention is a common or indispensable part of management are succinctly reviewed. Pathophysiology and rational approaches to diagnosis are emphasized.

Differentiated thyroid cancer in children

Differentiated thyroid cancer in children remains a controversial disease entity. Its incidence has markedly declined over the last decade since the use of radiotherapy in the treatment of benign conditions of the head, neck, and thorax was abandoned. Other etiologic factors have become relatively more important. The clinical presentation of childhood thyroid cancer is similar to that found in adults, except for a higher frequency of local and distant metastases at the time of initial diagnosis. The specificity and sensitivity of diagnostic tests are limited; however, like in adults, fine-needle aspiration compares favorably with other available diagnostic methods. The therapeutic approach to a child with thyroid cancer represents the most controversial issue associated with the disease. This review provides a discussion of the rationale for the different therapeutic options and emphasizes the excellent prognosis and survival rates, especially when patients are subjected to aggressive treatment with total thyroidectomy followed by the administration of radioactive iodine.

Use of ultrasound in childhood thyroid disorders

Thyroid ultrasound findings in 55 patients aged 6 days to 19 years were reviewed to assess the importance of this technique in evaluating childhood thyroid disorders. Findings were correlated with the available clinical, radionuclide, and pathologic data. In 25 patients with diffuse thyroid lesions (thyroiditis, Graves disease, euthyroid goiter, iodine-induced goiter, goitrous cretinism), ultrasound revealed only homogeneous thyroid enlargement or a nonspecific patchy echo pattern. In two infants with poorly visualized glands on radionuclide scans, ultrasound confirmed the presence of anatomically normal thyroid tissue. Twenty patients had at least one focal thyroid lesion seen by ultrasound, including nodules not detected by palpation in one child or by technetium scan in three. Thyroid malignancies were found in four of 13 patients with solitary thyroid nodules, occurring in two of four patients with echogenic nodules, two of five children with complex lesions, and none of four with echofree nodules. Thyroid ultrasound is a sensitive, noninvasive means of evaluating thyroid anatomy. Because it can detect thyroid tissue in the neck not seen on radionuclide scan in patients at all ages and can define the number and consistency of focal lesions, this technique offers definite advantages in assessing a variety of childhood thyroid disorders.

Solitary thyroid nodules in children and adolescents

Thirty-nine children and adolescents with a solitary nodule of the thyroid gland were seen over a 16-yr period and 35 had their nodules removed surgically. All of the patients had preoperative thyroid scintiscans, of which 27 showed a cold nodule. The most common cause of solitary thyroid nodules was follicular adenoma. Five of the 27 cold nodules were malignant (18.5%) while no malignancies were present in the warm or hot nodules. Available diagnostic methods of attempting differentiation of benign from malignant solitary nodules are reviewed and an approach to the clinical management of such nodules as derived from our experience is presented.