Severe thyrotoxicosis caused by an ectopic intrathoracic goiter

Area of Science:

• Endocrinology
• Nuclear Medicine
• Thoracic Surgery

Background:

• Ectopic thyroid tissue can occur within the thorax, but thyrotoxicosis from such masses is rare.
• Previous cases of intrathoracic ectopic thyroid tissue were either nontoxic or directly connected to the orthotopic thyroid gland.

Observation:

• A 71-year-old woman presented with severe thyrotoxicosis.
• Imaging revealed a multinodular intrathoracic goiter separate from the normally located thyroid gland.

Findings:

• The intrathoracic mass was confirmed to be of thyroid origin via Tc-99m sodium pertechnetate scintigraphy.
• This represents a rare instance of a fully ectopic, functional thyroid goiter causing thyrotoxicosis.

Implications:

• Highlights the importance of considering ectopic thyroid tissue in the differential diagnosis of thyrotoxicosis, even when presenting as an isolated intrathoracic mass.
• Tc-99m scintigraphy is a valuable tool for confirming the thyroid origin of ectopic masses.
• This case expands the understanding of intrathoracic goiter presentations and their potential to cause severe hyperthyroidism.