From the Guidelines
Parathyroid adenoma is a benign tumor that causes primary hyperparathyroidism, leading to excessive parathyroid hormone production, hypercalcemia, and potential symptoms such as bone pain, kidney stones, and cognitive impairment, and is typically treated with surgical removal of the affected gland. The condition is characterized by autonomous parathyroid hormone (PTH) secretion, which disrupts calcium homeostasis in the body, resulting in elevated blood calcium levels and decreased phosphate levels 1.
Key Characteristics of Parathyroid Adenoma
- Primary hyperparathyroidism (PHPT) is the most common form of hyperparathyroidism, typically resulting from a single parathyroid adenoma (80%) 1
- PHPT can also occur from multiple adenomas, parathyroid hyperplasia, or, rarely, parathyroid carcinoma (<1%) 1
- The condition is more common in women, with an incidence of 66 per 100,000 person-years, and 25 per 100,000 person-years in men 1
- Most cases are sporadic, although hereditary causes exist, including multiple endocrine neoplasia types 1 and 2A as well as familial hyperparathyroidism 1
Diagnosis and Treatment
- Diagnosis typically involves blood tests showing elevated calcium and PTH levels, followed by imaging studies like ultrasound, sestamibi scan, or 4D-CT to locate the adenoma 1
- The definitive treatment is surgical removal of the affected gland (parathyroidectomy), which resolves symptoms in most patients and normalizes calcium levels 1
- There are two accepted curative operative strategies for PHPT: bilateral neck exploration (BNE) and minimally invasive parathyroidectomy (MIP) 1
- MIP is often performed as it conveys the benefits of shorter operating times, faster recovery, and decreased perioperative costs, but requires confident and precise preoperative localization of a single parathyroid adenoma 1
From the Research
Parathyroid Adenoma Overview
- Parathyroid adenomas are the most common cause of primary hyperparathyroidism (PHPT), accounting for 80-85% of cases 2, 3, 4
- PHPT is characterized by an excessive and abnormally regulated secretion of parathyroid hormone (PTH) from the parathyroid glands, leading to altered calcium and phosphorus metabolism 3
Clinical Presentation
- Patients with parathyroid adenomas may present with non-specific signs and symptoms of hypercalcemia, such as anorexia, nausea, vomiting, polyuria, dehydration, abdominal pain, weight loss, fatigue, muscular weakness, irritability, and lethargy 3, 5
- Some patients may also experience skeletal fragility, nephrolithiasis, and nephrocalcinosis 2
- Giant parathyroid adenomas (GPTA) may have a distinct clinical presentation, with higher pre-operative calcium and PTH levels, but potentially less severe symptoms due to local mass effects 4
Treatment and Management
- Surgery is the gold standard treatment for parathyroid adenomas, with parathyroidectomy advised in patients with significant hypercalcemia, impaired renal function, renal stones, or osteoporosis 2, 3
- Medical management may be considered in patients with mild asymptomatic disease, contraindications to surgery, or failed previous surgical intervention 2
- Cinacalcet, a calcimimetic agent, has been shown to effectively lower serum calcium and PTH levels, and may also reduce the size of parathyroid adenomas 6
Complications and Outcomes
- Untreated parathyroid adenomas can lead to severe hypercalcemia, which can be life-threatening if left unrecognized and untreated 5
- Post-operative hypocalcemia is a common complication, but recurrent or persistent PHPT is less common 4
- Giant parathyroid adenomas may have a higher rate of atypia, but are mostly benign 4