Aim: To report on two cases of childhood thyroid minimally invasive follicular carcinoma (MIFC) to highlight the clinical features, laboratory findings and diagnosis of this rare disease.
Methods: The patients' age, gender, clinical features, laboratory findings, pathology and therapy were reviewed. Immunohistochemistry analysis was performed on the resected masses section.
Results: From 2000 to 2008, a total of 15 cases of thyroid cancer were confirmed by pathological analysis, which account for about 2.16% of all malignant solid tumours. They included nine of thyroid papillary carcinoma, two of MIFC and one of undifferentiated thyroid carcinoma. For the two children with MIFC, one was an 8-year-boy and one was a 12-year-old girl. Thyroid mass was found as the primary sign. Imaging findings showed well-defined heterogeneous mass and radionuclide scintigraphy with 99mTc demonstrated small cold nodules in the right lobe of thyroid in two cases. Histopathology confirmed the diagnosis of MIFC. Immunohistochemical staining was positive for thyroglobulin, thyroid transcription factor-1, galectin-3, Hector Battifora mesothelial antigen-1, cytokeratin-AE1/AE3, cytokeratin-19, proliferating cell nuclear antigen and E-cadherin in two cases, and S-100 in one case, while CD56, vimentin and desmin were negative. One case was undertaken lobectomy and the other was undertaken subtotal thyreoidectomy with L-T4 replacement therapy.
Conclusion: MIFC is exceedingly rare in children and should be included in the differential diagnosis of thyroid mass. The diagnosis of MIFC depends mainly on the pathological findings.