SSTR Expressing Mediastinal Ectopic Thyroid: A Rarity Unveiled.

Area of Science:

• Nuclear medicine
• Endocrinology
• Radiology

Background:

• Ectopic thyroid tissue, while uncommon, can occur alongside a normally located thyroid gland.
• Technetium pertechnetate scintigraphy is the standard imaging modality for assessing thyroid tissue, including ectopic locations.
• Gallium-68 DOTANOC positron emission tomography-computed tomography (PET-CT) uptake in mediastinal ectopic thyroid tissue is rarely documented.

Purpose of the Study:

• To report a unique case of ectopic mediastinal thyroid tissue with atypical imaging characteristics.
• To investigate the utility of Gallium-68 DOTANOC PET-CT in evaluating ectopic thyroid tissue that does not concentrate technetium pertechnetate.

Main Methods:

• Case presentation of a patient with an ectopic mediastinal thyroid mass.
• Comparison of imaging findings between technetium pertechnetate scintigraphy and 68Ga-DOTANOC PET-CT.
• Correlation with the presence of eutopic cervical thyroid tissue.

Main Results:

• The ectopic mediastinal thyroid mass demonstrated no uptake on technetium pertechnetate scan.
• Significantly increased uptake was observed on 68Ga-DOTANOC PET-CT in the ectopic mediastinal thyroid mass.
• The eutopic cervical thyroid showed normal technetium pertechnetate uptake and physiological mild DOTANOC uptake.

Conclusions:

• Ectopic mediastinal thyroid tissue can exhibit variable uptake patterns on nuclear imaging.
• 68Ga-DOTANOC PET-CT may be a valuable tool for detecting and characterizing ectopic thyroid tissue, especially when conventional scans are negative.
• This case expands the understanding of imaging modalities for ectopic thyroid tissue.