Intrathyroidal parathyroid adenoma mimicking thyroid cancer

Area of Science:

• Endocrinology
• Surgical Pathology
• Oncology

Background:

• Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia, typically due to a single parathyroid adenoma (PA).
• Parathyroid adenomas can occur in ectopic locations, including within the thyroid gland, accounting for 1-6% of cases.
• Intrathyroidal parathyroid adenomas present diagnostic challenges due to potential confusion with thyroid lesions.

Observation:

• A case of a large, partially cystic intrathyroidal parathyroid adenoma initially misdiagnosed as a malignant thyroid nodule is presented.
• Cytological similarities between thyroid malignant cells and parathyroid cells complicated the initial diagnosis.
• A negative sestamibi scan further contributed to diagnostic uncertainty.

Findings:

• The case highlights the diagnostic difficulties in distinguishing intrathyroidal parathyroid adenomas from thyroid nodules.
• Histological and clinical features are crucial for accurate diagnosis of these rare lesions.
• Misdiagnosis led to more invasive surgery than typically required for a single parathyroid adenoma.

Implications:

• Clinicians must be aware of the cytological similarities between parathyroid and thyroid tissues to ensure accurate diagnosis.
• Vigilance and a comprehensive diagnostic approach are essential for optimal patient care in cases of suspected intrathyroidal parathyroid adenoma.
• Improved diagnostic strategies are needed to prevent overtreatment of intrathyroidal parathyroid adenomas.