Parathyroid Lesion
A parathyroid lesion is an abnormal growth or enlargement involving one or more of the parathyroid glands, the small glands located behind the thyroid gland in the neck. These glands regulate calcium levels in the body by producing parathyroid hormone (PTH). Most parathyroid lesions are benign and include adenomas, hyperplasia, and less commonly cysts. Parathyroid cancer is rare. Many parathyroid lesions are first suspected because of abnormal calcium or PTH blood test results rather than a visible or palpable neck mass.
What is it?
The parathyroid glands are typically four small glands located behind the thyroid gland in the neck, although their exact position and number can vary between individuals. Their primary role is to maintain normal calcium balance by releasing parathyroid hormone, which acts on the bones, kidneys, and intestines.
When one or more parathyroid glands becomes enlarged or overactive, excessive PTH may be produced, leading to elevated blood calcium levels—a condition known as primary hyperparathyroidism.
Parathyroid lesions may take several forms:
Parathyroid adenoma: a benign tumor affecting a single gland and the most common cause of primary hyperparathyroidism
Parathyroid hyperplasia: enlargement of multiple glands, sometimes associated with inherited syndromes
Parathyroid cysts: uncommon fluid-filled lesions
Parathyroid carcinoma: a rare malignant tumor
Some people have no symptoms and are diagnosed after routine blood work reveals elevated calcium levels. Others develop symptoms related to high calcium levels, kidney stones, bone loss, fatigue, or gastrointestinal complaints.
Diagnosis usually begins with blood tests showing elevated calcium and PTH levels. Once biochemical evidence of hyperparathyroidism is established, imaging is used to localize the abnormal gland before surgery rather than to establish the diagnosis itself.
Ultrasound of the neck is commonly the first imaging study because it provides detailed visualization of the thyroid and adjacent parathyroid region.
Sestamibi nuclear medicine scans help identify overactive parathyroid tissue by showing increased tracer uptake. 4D CT is increasingly used for more precise localization, especially when ultrasound or sestamibi imaging is inconclusive or when the abnormal gland is located in an unusual position such as the chest.
Important to Know
The primary treatment for symptomatic or progressive primary hyperparathyroidism is surgical removal of the abnormal gland, known as parathyroidectomy. When performed by experienced endocrine surgeons, surgery has high success rates and may help prevent complications such as osteoporosis, kidney stones, and long-term calcium imbalance.
Patients who do not meet criteria for surgery may be monitored with periodic blood tests, imaging, and bone density studies. Medications may sometimes be used to help manage calcium levels.
Imaging plays an important role in surgical planning, and multiple imaging studies are often combined because no single test identifies every parathyroid lesion.
Care is commonly coordinated among endocrinologists, endocrine surgeons, radiologists, and nuclear medicine specialists.
Red flag symptoms include severe fatigue, confusion, persistent nausea or vomiting, severe abdominal pain, dehydration, recurrent kidney stones, abnormal heart rhythms, or new bone fractures. These symptoms require prompt medical evaluation, especially when calcium levels are significantly elevated.