A case of dual ectopy thyroid along the thyroglossal tract demonstrated on 99mTc-Pertechnatate hybrid single photon emission computed tomography/computed tomography
The present case report is about a 10-year-old girl who presented with anterior midline neck swelling since 6 months, which was gradually increasing in size. On evaluation, she was found to have hypothyroidism without evidence of growth retardation. On local examination, a swelling 2 × 2 cm size, cystic, well-defined with a smooth surface neither compressible nor reducible was palpated just below the hyoid bone, which was moving up with protrusion of tongue and with deglutition, but was not trans-illuminant. Serum biochemistry revealed T3 = 86 ng/dL (normal, 70-200 ng/dL), T4 = 4.3 μg/dL (normal, 4.5-12.5 μg/dL) and thyroid-stimulating hormone level of 27 μIU/mL (normal, 0.5-4.7 μIU/mL). With a provisional diagnosis of sub-hyoid thyroglossal cyst, patient was referred for a technetium thyroid scan to rule out functioning thyroid tissue in the cyst. 99mTc-pertechnatate thyroid scan revealed a midline focus of tracer uptake corresponding to the palpable neck swelling suggestive of ectopic functioning thyroid tissue. No tracer uptake was noted in the region of the thyroid bed. In addition, a small linear streak of tracer activity was seen to extend superiorly [] from the ETT in the neck. SPECT/CT of the neck revealed ETT on the right side of the thyroid cartilage, in the sub-hyoid location; in addition to this another ectopic rest of thyroid tissue was noted in the midline floor of the mouth. Tracer was also seen to extend along a tract, which was well-appreciated on sagittal section []. Patient was started on thyroid supplementation therapy.