Endocrine Abstracts

Introduction: Thyroid carcinoma in childhood is rare, but may present with distant metastases. We present an unexpected diagnosis of follicular–variant papillary thyroid carcinoma (FVPTC) presenting to acute services with cyanosis.

Case report: An 11-year old boy presented to A&E with a two month history of cyanosis, worse with exertion, but not associated with respiratory distress or limitation of exercise tolerance. He had peripheral cyanosis, clubbing and oxygen saturations 78% (air). CT chest showed bilateral, extensive miliary nodules, in keeping with interstitial lung disease. Differential diagnoses included sarcoidosis, tuberculosis and pulmonary alveolar microlithiasis. Following lung biopsy, histology showed FVPTC; subsequent neck examination then revealed a thyroid mass with bilateral cervical lymphadenopathy, confirmed on thyroid ultrasound and MRI neck. Thyroid function test (TFT) was normal (TSH, 4.4 mU/l and FT₄, 13.1 pmol/l). After radical thyroidectomy and neck dissection, histology confirmed FVPTC. Full lymph-node resection was not possible. MRI brain showed four distinct lesions; abdominal CT showed bilateral renal metastases. TFT remained normal post-operatively, but after one cycle of radio-iodine therapy, levothyroxine supplementation was introduced (75 μg once daily). Papillary thyroid cancer is the commonest differentiated thyroid cancer; FVPTC is a common subtype. Regional lymph-node involvement is common in young patients (60–80%), 10–20% have distant metastases. Females predominate; 12% have history of local irradiation; 10% have family history. Adult series have shown younger age and lung-metastases only are associated with good prognosis. A paediatric series of 83 patients aged under 21 at diagnosis of differentiated thyroid carcinoma with distant metastases showed 100% 10-year survival.

Conclusion: This case highlights the importance of considering unlikely causes of common presentations. FVPTC in young patients with widely metastatic disease tends to be extremely radio-iodine responsive, with high cure rate, however this case has more wide-spread metastases than previously reported and the reversibility of the lung disease is unknown.