14-15 Abstract Papillary thyroid carcinoma may be multifocal in up to 50% of affected children. Surgeons must weigh the higher risks of recurrence when surgi- cal resection is less than subtotal thy- roidectomy against the higher risks of complications with subtotal/total thy- roidectomy. An 11-year-old girl pre- sented to our surgical department with a thyroid mass. Computed tomography (CT) revealed a lesion, missed by ultrasonography, which reversed the decision to perform con- servative thyroid surgery. The lesion proved to be non-neoplastic. CT may be a useful adjunct when ultrasound demonstrates a solitary lesion and conservative surgery is considered, and may prove to be able to distin- guish neoplastic from non-neoplastic lesions based on contrast enhance- ment characteristics, but caution is advised in assuming that all nodules are neoplastic. Introduction The literature presents two views regarding the treatment of paediatric papillary thyroid carcinoma. There are those supporting conservative sur- gical procedures and those supporting subtotal or total thyroidectomy.1-7 Surgeons must weigh the higher risks of recurrence when surgery is less than subtotal thyroidectomy against the higher risks of complications with subtotal/total thyroidectomy. CT may be a useful adjunct when ultrasound demonstrates a solitary lesion and conservative surgery is considered, and may prove to be able to distin- guish neoplastic from non-neoplastic lesions based on contrast enhance- ment characteristics. Case report An 11-year-old girl presented to our surgical department with a thy- roid mass. Computed tomography (CT) revealed a finding, missed by ultrasonography, which reversed the decision to perform conservative thy- roid surgery. Ultrasound demonstrat- ed a single lesion in the left thyroid lobe (Fig. 1). CT confirmed the pri- mary lesion in the left thyroid lobe measuring 2.2 x 2.2 x 3 cm, but also revealed a small right lobe lesion mea- suring 0.1 x 0.2 x 1.5 cm (Fig. 2a), which was not observed on ultra- sound. Contrast CT showed enhance- ment of the left lobe nodule, but no enhancement of the right lobe nodule (Fig. 2b). More extensive surgery than originally planned was undertaken based on this finding, presuming that the right nodule was also a possible focus of malignancy. Pathological examination diagnosed the larger nodule to be a papillary thyroid carci- noma with vascular invasion but con- cluded that the smaller nodule was not neoplastic. Discussion In the consideration of surgical treatment of paediatric papillary thy- roid carcinoma, the higher risks of CASE REPORT 14 SA JOURNAL OF RADIOLOGY • July 2005 CT scanning may adversely influence choice of surgery in paediatric papillary thyroid carcinoma - a note of caution S Andronikou MB BCh, FCRad (Diag) (SA), FRCR (Lond) Formerly: Department of Paediatric Radiology Red Cross Children’s Hospital and University of Cape Town Fig. 1. Ultrasound demonstrates the inhomo- geneous left thyroid lobe mass (white arrows) and the adjacent carotid and jugular vessels (black arrows). Fig. 2a. Non-contrast CT scan of the neck shows the low-density nodule in the left thy- roid lobe (whte arrow) with a thin rim of normal dense thyroid parenchyma anteriorly (white arrowhead). A small second low-density lesion is demonstrated in the right lobe later- ally (black arrow). 14-15 8/1/05 12:31 PM Page 14 recurrence when surgery is less than subtotal thyroidectomy must be weighed against the higher risks of complications with subtotal/total thy- roidectomy. Complications of subto- tal/total thyroidectomy include hypoparathyroidism in up to 30% of patients and recurrent laryngeal nerve injury in up to 11% of patients.1-7 Papillary thyroid carcinoma may be multifocal in up to 50% of affected children1-3,5,7 and, as a result, recur- rence rates are higher when less than subtotal thyroidectomy is performed.2 Residual thyroid tissue also diminish- es the specificity of thyroglobulin as a tumour marker and interferes with radioiodine as a diagnostic tool post- operatively.3 Some authors maintain, however, that there is no evidence that patients who undergo total thyroidec- tomy fare better than those with con- servative surgery at long-term follow- up,2,3,5 even though recurrence in thy- roid remnants is higher in children than in adults.6 Ultrasonography is used to rule out thyroid anomalies, to determine if nodules are solitary or multiple, and to determine if nodules are cystic or solid.6,8 A cystic nodule does not exclude malignancy8 and therefore imaging is largely directed toward excluding multifocality. The sensitivi- ty for ultrasound detection of micro- scopic nodules (less than what size?) is quoted to be 50%.4 When there is a solitary nodule, fine needle aspira- tion (FNA) may be sufficient to confirm or exclude malignancy4,8 and conservative surgery can be consid- ered. Scintigraphy in patients who have undergone ultrasonography and FNA is not expected to contribute useful information in such cases and has been omitted in some protocols.8 CT scanning has only been recom- mended for the evaluation of paedi- atric thyroid lesions by two authors.1,6 In our patient, CT proved to be more sensitive than ultrasound in detecting the small right thyroid lesion. Although the small lesion was not neoplastic, it led to more aggressive surgery. With non-contrast CT, these lesions are seen as low-density lesions against the dense background of iodine-rich normal parenchyma (Fig. 2a). Conversely, enhancement of a small lesion may make it less conspic- uous on CT compared with the adja- cent dense thyroid tissue. Contrast CT in our patient showed enhancement of the primary neoplastic left lobe nodule, but no enhancement of the non-neoplastic right lobe nodule. This may be a means of differentiating neoplastic from non-neoplastic lesions, but this remains to be proved. Conclusion Identification of more than one lesion in childhood thyroid carcino- ma will affect surgical management in centres where conservative surgery is preferred, and imaging must be directed towards identification of these. CT may be a useful adjunct when ultrasound demonstrates a soli- tary lesion and conservative surgery is considered, and may prove to be able to identify small lesions and possibly distinguish neoplastic from non-neo- plastic lesions based on contrast enhancement characteristics. How- ever, prospective studies to compare CT and ultrasound detection of thy- roid lesions are difficult to perform because of the rarity of thyroid malig- nancy in childhood (1 - 1.5% of all malignancies in this age group).5,7 References 1. La Quaglia MP, Black T, Holcomb GW 3rd, et al Differentiated thyroid carcinoma: Clinical char- acteristics, treatment and outcome in patients under 21 years of age who present with distant metastases. A report from the surgical discipline committee of the children’s cancer group. J Pediatr Surg 2000; 35: 955-960. 2. Welch Dinauer CA, Tuttle RM, Robie DK, Mc Clellan DR, Francis GL. Extensive surgery improves recurrence-free survival for children and young patients with class I papillary thyroid carcinoma. J Pediatr Surg 1999; 34: 1799-1804. 3. Kuefer MU, Moinuddin M, Heideman RL, et al. Papillary thyroid carcinoma: demographics, treatment and outcome in eleven pediatric patients treated at a single institution. Med Pediatr Oncol 1997; 28: 433-440. 4. Karguzel G, Tanyel FC, Buyukpamukcu N, Hicsonmez A. Is there any predictive character- istic for malignancy in thyroid enlargements during childhood? Eur J Pediatr Surg 1996; 6: 70-74. 5. Massimino M, Gasparini M, Ballerini E, Del Bo R. Primary thyroid carcinoma in children: a ret- rospective study of 20 patients. Med Pediatr Oncol 1995; 24: 13-17. 6. Gorlin JB, Salan SE. Thyroid cancer in child- hood. Endocrinol Metab Clin North Am 1990; 19: 649-662. 7. Desjardins JG, Bass J, Leboeuf G, et al. A twen- ty-year experience with thyroid carcinoma in children. J Pediatr Surg 1988; 23: 709-713. 8. Hung W. Solitary thyroid nodules in 93 children and adolescents: a 35 years experience. Horm Res 1999; 52: 15-18. CASE REPORT 15 SA JOURNAL OF RADIOLOGY • July 2005 Fig. 2b. Post contrast CT scan of the same region demonstrates inhomogeneous enhancement of the larger nodule (white arrow) making it more difficult to differentiate from normal parenchyma. The small right lobe lesion does not enhance and is now more evident (black arrow). 14-15 8/1/05 12:31 PM Page 15