Histological Examination of Ectopic Thyroid Tissue in an 88-year-old Caucasian Female: A Case Report




Journal Title

Journal ISSN

Volume Title



Background: Ectopic thyroid tissue (ETT) is a rare developmental abnormality that accounts for 1% of all mediastinal tumors and has a higher prevalence in females. ETT classically presents as an encapsulated mass separate from the normal subhyoid thyroid gland present on the anterior neck. Case studies have reported that ETT can arise in the mouth, oropharynx, subclavicular area, or mediastinum. Unless large enough to compress the surrounding tissues, individuals with ETT are typically asymptomatic. Therefore, ETT is often an incidental finding during imaging studies, surgery, or at autopsy. Histologically, ETT usually appears identical to "normal" thyroid tissue.

Case Information: During routine dissection, an 88-year-old Caucasian female with a cause of death of renal cancer presented with an encapsulated, solitary nodule located at the intersection between the thoracic cavity and superior mediastinum (2.0 x 1.0 x 1.5 cm). The nodule was densely adherent to the medial aspect of the right lung's apex, leaving behind a notable impression following extraction. No attachments to the thyroid proper were noted. Tan-brown, glassy, and multinodular cut surfaces were grossly appreciated following sectioning. Histological examination demonstrated the nodule was entirely composed of benign thyroid tissue with variable sized colloid follicles. No suspicious foci were identified. It is indeterminate if this nodule influenced the donor’s thyroid hormone levels due to the lack of access to a thyroid panel. Next, the thyroid proper was examined to reveal an enlarged, asymmetric gland with disconnected lobes. No obvious isthmus was present. The total gland weighed 85 grams. The external surface of the thyroid proper was tan-brown, bosselated, and featured an intact capsule. The left lobe (5.0 x 3.4 x 1.7 cm; 9 grams) was markedly smaller when compared to the enlarged right lobe (8.6 x 5.2 x 3.4 cm; 76 grams). Sectioning of the left lobe revealed tan, homogenous, and grossly unremarkable cut surfaces; the right lobe revealed tan-brown to maroon, firm, and multinodular cut surfaces. Additionally, a white, soft, and ill-defined area, with intervening colorless gelatinous material, was noted at roughly mid-pole of the right lobe.

Conclusion: This report describes a rare case of ETT and other relevant anatomical findings in an 88-year-old Caucasian female. These findings will further contribute to a scarcely documented developmental abnormality in the literature.