Fig. 4

A patient in long-term follow-up affected by unifocal papillary carcinoma with extra-thyroid tumor extension (T4aN0M0) already submitted to total thyroidectomy and radioiodine ablation. Diagnostic planar 131I-WBS after rh-TSH stimulation, in both anterior and posterior views (a, b), and planar neck/thorax anterior and posterior views (c, d), do not show any foci of pathologic radioiodine uptake. SPECT/CT in coronal (e, f), sagittal (g, h) and transverse (i, l) fusion images evidenced one radioiodine-avid focus (white arrows) in right laterocervical region adjacent to the sub-mandibular gland, in a posterior position, classifying it as lymph node metastasis also visible at CT images. Thyroglobulin levels were undetectable in basal conditions reaching values of 7.8 ng/ml after rh-TSH stimulation; anti-thyroglobulin antibodies were negative. Thus, the patient underwent a second therapeutic dose of radioiodine