The intrathyroidal hyperfunctioning parathyroid gland.

Area of Science:

• Endocrinology
• Surgical Pathology
• Oncology

Background:

• Primary hyperparathyroidism is typically caused by parathyroid adenomas or hyperplasia, usually located ectopically in the neck.
• Intrathyroidal parathyroid glands are an uncommon cause of hyperparathyroidism, posing diagnostic and surgical challenges.

Purpose of the Study:

• To report and analyze cases of primary hyperparathyroidism resulting from hyperfunctioning intrathyroidal parathyroid glands.
• To discuss the differential diagnosis and diagnostic modalities for intrathyroidal parathyroid lesions.

Main Methods:

• Case series reporting six patients with hyperfunctioning intrathyroidal parathyroid glands.
• Review of clinical presentations, surgical findings, and histopathological diagnoses.
• Discussion of immunocytochemical staining for parathormone (PTH), thyroglobulin, and calcitonin.

Main Results:

• Five cases involved intrathyroidal parathyroid adenomas (four female, aged 40-70) and one involved intrathyroidal parathyroid carcinoma (male, 55).
• Thyroidectomy was performed in adenoma cases when glands were not found in typical locations.
• Carcinoma presented with hypercalcemia and a thyroid mass; differential diagnosis included thyroid follicular adenoma and medullary carcinoma.

Conclusions:

• Intrathyroidal parathyroid glands are a rare but significant cause of primary hyperparathyroidism.
• Accurate diagnosis requires differentiating these lesions from thyroid neoplasms, with immunocytochemistry being crucial.
• Surgical management may involve thyroidectomy when parathyroid glands are intrathyroidal.