Cinematic rendering of ectopic thyroid tissue

A 43-year-old woman was diagnosed with a left anterior mediastinal mass on a plain chest computed tomography (CT) scan performed 3 days prior to hospital admission, without significant clinical symptoms. Contrast-enhanced CT revealed a calcification-containing anterior mediastinal mass with marked heterogeneous enhancement (Figure 1A-1C). Cinematic rendering highlighted the surface of the mass, revealing the left brachiocephalic vein passing through it, while normal thyroid tissue remained intact (Figure 1D,1E). The patient underwent surgical resection of the mass, and pathology confirmed ectopic thyroid tissue (ETT).

Figure 1 Images of ectopic thyroid tissue in a 43-year-old woman. (A) Axial non-enhanced CT scan reveals an anterior mediastinal mass containing calcifications, with a low-density area indicating necrosis within the lesion (white arrow). (B) Axial contrast-enhanced CT scan demonstrates marked heterogeneous enhancement in the lesion (white arrow). (C) Coronal reconstruction illustrates the lesion’s close anatomical relationship with surrounding structures, such as left mediastinal pleura (green arrow), the thymic vein (red arrow) and pericardium (blue arrow), showcasing an enhancement pattern consistent with the normal thyroid gland (black star). (D,E) Cinematic rendering-CT imaging clearly demonstrates that the left brachiocephalic vein traverses and courses along the external surface of the mass, providing a detailed and anatomically precise visualization of the spatial relationship between the vascular structure and the adjacent pathological formation. Notably, the thyroid gland maintained its normal shape and position. CT, computed tomography.

ETT is very rare, with an incidence of about 1 per 100,000–300,000. Mediastinal ETT accounts for less than 1% of all mediastinal tumors (1). Usually, mediastinal ETT cases are euthyroid and asymptomatic, often found incidentally during routine chest radiography. CT-based cinematic rendering offers a detailed three-dimensional view of the mass’s anatomic location, adjacent structures, morphology, and blood supply. This information is crucial for accurate treatment planning and helps healthcare professionals make informed decisions on surgical and therapeutic approaches.

Acknowledgments

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Footnote

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-aw-2338/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

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References

1. Aziz J, Murthy R. Mediastinal ectopic thyroid tissue: a rare but important diagnosis. J Thorac Dis 2023;15:6388-9. [Crossref] [PubMed]