ESPR 2013

Paediatric Thyroid Masses

Introduction

CS Parsons, H Stirling, C Miller & EJ Helm

Grave’s Disease

Simple & Complex Nodules

Review of literature shows that thyroid nodules are relatively rare in the first two decades of life. The risk of malignancy in paediatric thyroid nodules is much higher with a recently reported incidence of 26.4%.

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Ultrasound Features of Malignancy 1-3

Solitary solid lesion Hypoechoic lesion Subcapsular localization

Aims

Irregular margins

Ø  To assess the referral pattern and demographics of thyroid masses in a paediatric population at a large secondary care centre. Ø  To summarise the clinical and radiological characteristics of thyroid pathology in children. Ø  To emphasise the role of imaging in management of thyroid disease.

Heterogeneous appearance Microcalcifications Intranodular high colour Doppler flow Regional lymphadenopathy Fig 2: Large anechoic thin-walled nodule with no adverse features present.

Table 2

Methods & Materials The study group (n = 500) was obtained by analysing the reports from all neck and thyroid ultrasounds performed on all patients aged 16 years or less between 01/01/2006 to 01/02/2013.

Results The majority of scans were normal (14.2%), demonstrated lymphadenopathy (45.6%) or abscess formation (6.8%). 14.4% of the group (n = 72) were referred to evaluate the thyroid of which 6.2% were found to have thyroglossal cysts. Clinical presentation of the remainder (n = 41) is summarized in table 1. Presentation Swelling/ Goitre Focal Lesion Hypothyroid Hyperthyroid Coincidental

Frequency (%) 2.80 1.00 1.80 1.60 0.20

Age (yrs) 14.09 (8.83 – 16.88) 16.28 (15.42 – 16.88) 6.06 (0.08 – 15.17) 13.09 (2.75 – 15.83) 14.75

Table 1: Clinical presentation of paediatric thyroid masses.

The final diagnosis following clinical evaluation, testing of thyroid function and antibodies and histological analysis of FNA samples are summarised in figure 1.

Figs 9&10: Coarsened echogenic appearance of a diffusely enlarged thyroid, with increased colour Doppler signal. Thyroid function tests confirmed Grave’s disease.

Papillary Thyroid Carcinoma Figs 3&4: Solitary mixed echogenic lesion with eccentric solid portion demonstrating high colour Doppler flow. Histology confirmed a complex colloid cyst.

Multinodular Goitre

Figs 5&6: Typical features of a multinodular goitre. Multiple anechoic lesions within an enlarged thyroiid. No significant intranodular Doppler flow is seen.

Indications For FNA 4,5 Ø  Nodule ≥ 1.0 cm diameter if there are microcalcifications present. Ø  Nodule ≥ 1.5 cm if the nodule is solid or if there are coarse calcifications within the nodule. Ø  Nodules < 1.0 cm whenever clinical information or ultrasound features raises suspicion about the presence of a malignancy.

Thyroiditis Fig 1: Final pathological diagnosis following clinical, radiological and histological evaluation.

Choice of Imaging Ultrasound remains the method of choice for thyroid gland structure. Ultrasound features of malignancy are described in table 2; distinguishing between benign and malignant lesions on ultrasound alone can be difficult. Progression to FNA is essential if any sinister features are present. Size of nodule will also influence the choice to perform FNA.

Figs 11&12: Solitary solid hyperechoic lesion demonstrating intranodular colour Doppler flow. Pathological examination confirmed papillary thyroid carcinoma.

Conclusions Ø  Despite paediatric thyroid cancer being relatively rare, there is a much higher risk of malignancy in a thyroid nodule. Therefore careful evaluation of the thyroid and correlation with clinical, serological and histological factors is essential. Ø  Most malignant nodules are more likely to be solid and hypoechoic; a large cystic component favours a benign lesion although a significant proportion of papillary carcinomas will have a cystic component.

Bibliography 1.  2.  3.  4. 

Figs 7&8: Transverse views of hyperechoic thyroid with significant Power Doppler signal throughout the parenchyma. Serological testing confirmed Hashimoto’s thyroiditis.

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