Malignancy Risk Within Hyperfunctioning Thyroid Nodules: Clinicopathologic Features and Diagnostic Implications

Area of Science:

• Endocrinology
• Oncology
• Nuclear Medicine

Background:

• Hyperfunctioning thyroid nodules are typically considered low-risk for malignancy.
• Limited data exists on the clinicopathologic features of true hyperfunctioning thyroid neoplasms.

Purpose of the Study:

• To characterize true hyperfunctioning thyroid neoplasms.
• To determine their diagnostic implications and frequency in surgically treated patients.

Main Methods:

• Retrospective review of 82 hyperthyroid patients with toxic nodules on scintigraphy.
• Lesion-level imaging-pathologic correlation for 25 surgically treated patients.
• Definition of true hyperfunctioning neoplasms by imaging-pathologic correlation.

Main Results:

• Seven of 25 surgically treated patients (28.0%) had hyperfunctioning carcinoma or tumors of uncertain malignant potential (UMP).
• Hyperfunctioning neoplasms were larger and more often follicular-patterned than benign nodules.
• Observed frequency in the full cohort was 8.5%, but this is subject to surgical selection bias.

Conclusions:

• Hyperfunctioning status does not exclude thyroid malignancy.
• The precise malignancy frequency in unselected hyperthyroid populations remains uncertain.