From the Guidelines
The most common type of parathyroid tumor is a parathyroid adenoma, which occurs in approximately 80% of primary hyperparathyroidism cases. This is based on the most recent and highest quality study available, which was published in the Journal of the American College of Radiology in 2021 1.
Key Characteristics of Parathyroid Adenomas
- They are benign (non-cancerous) growths that typically affect only one of the four parathyroid glands.
- These tumors cause excessive production of parathyroid hormone (PTH), leading to increased calcium levels in the blood.
- Most parathyroid adenomas are small, measuring less than 2 cm in diameter, and are composed of chief cells.
- They develop sporadically in most cases, though some may be associated with genetic conditions like Multiple Endocrine Neoplasia type 1 (MEN1).
Treatment and Prognosis
- The standard treatment for parathyroid adenomas is surgical removal of the affected gland (parathyroidectomy), which is curative in about 95% of cases, as supported by the study 1.
- Less common parathyroid disorders include parathyroid hyperplasia (affecting multiple glands), double adenomas, and parathyroid carcinoma (cancer), which is rare, accounting for less than 1% of cases, as noted in the study 1.
Clinical Considerations
- The diagnosis of primary hyperparathyroidism, often due to a parathyroid adenoma, is typically made through biochemical testing, including serum calcium and serum PTH levels, as outlined in the study 1.
- The management and treatment of parathyroid adenomas prioritize minimizing morbidity, mortality, and improving quality of life, which is achievable through accurate diagnosis and appropriate surgical intervention, as emphasized by the evidence 1.
From the Research
Types of Parathyroid Tumors
- The most common type of parathyroid tumor is a benign adenoma, which accounts for 85% to 90% of primary hyperparathyroidism (PHPT) cases 2, 3.
- Parathyroid adenomas are typically solitary and are the primary cause of PHPT, leading to excessive and uncontrolled secretion of parathyroid hormone (PTH) 4.
- Multiglandular disease, including multiple adenomas or hyperplasia, accounts for 10% to 15% of PHPT cases, while parathyroid carcinoma is rare, occurring in only 1% of cases 2, 3.
- Giant parathyroid adenomas, defined as weighing more than 3-3.5 grams, are a distinct entity and may have different clinical presentations and outcomes compared to non-giant adenomas 5.
Characteristics of Parathyroid Adenomas
- Parathyroid adenomas are usually small and do not have local mass effects, but giant adenomas can cause more severe symptoms due to their size 5.
- The size of parathyroid adenomas can be reduced with cinacalcet therapy, a calcimimetic that modulates the functions of the calcium-sensing receptor 6.
- Ectopic parathyroid adenomas can occur due to abnormal embryological migration of the parathyroid glands and can be difficult to localize preoperatively 2.