OVERVIEW

What is Fibrocystic Osteitis?

Fibrocystic osteitis appears to be a bone lesion on the surface, but its root cause does not lie in the bone itself. The origin of this disease is actually the parathyroid glands in the neck.

When various factors lead to excessive synthesis and secretion of parathyroid hormone (PTH) by the parathyroid glands, hyperparathyroidism (referred to as "hyperparathyroidism") occurs. If not detected early or treated effectively, the disease may progress to a stage where characteristic changes in the bones appear.

The bone undergoes dissolution and absorption, fibrous tissue proliferates, and the areas of bone dissolution expand, forming cystic bone defects. The fibrous tissue within degenerates and bleeds, accompanied by hemosiderin deposition, giving the tissue inside the cyst a brown (or tan) color—this is fibrocystic osteitis. Due to its distinctive color and appearance, it is also called a brown tumor.

This disease commonly affects long bones, ribs, clavicles, and the pelvic ring.

Patients typically present with slowly growing painful masses, which may compress surrounding tissues but generally do not metastasize. Imaging studies (such as X-rays) may reveal subperiosteal resorption in the fingers (or toes), skull, and long bones, as well as diffuse bone loss. Bone scans often show significant radionuclide uptake. Pathological examination of the lesion may reveal hemorrhage, multinucleated giant cells, and fibrous tissue components.

In summary, fibrocystic osteitis is a late-stage secondary bone lesion caused by hyperparathyroidism.

Is Fibrocystic Osteitis Common?

Fibrocystic osteitis is uncommon. This disease is primarily caused by primary or secondary hyperparathyroidism, with primary hyperparathyroidism being the most common. Approximately 0.1% to 5% of hyperparathyroidism patients may develop brown tumors as a secondary condition.

SYMPTOMS

What are the common manifestations of osteitis fibrosa cystica?

• Manifestations of hyperparathyroidism, among which recurrent urinary tract stones are the most common.
• Common symptoms of osteitis fibrosa cystica include subcutaneous masses, localized bone and joint pain, and fractures.

How does osteitis fibrosa cystica develop?

Osteitis fibrosa cystica primarily results from long-term untreated hyperparathyroidism, leading to bone dissolution and absorption, as well as fibrous tissue hyperplasia.

What severe consequences can osteitis fibrosa cystica cause?

As the condition progresses, the risk of fractures significantly increases, and severe cases may significantly impact quality of life.

CAUSES

What are the common causes of fibrous cystic osteitis?

Fibrous cystic osteitis primarily occurs as a consequence of prolonged untreated hyperparathyroidism. Therefore, the development of this condition is closely linked to hyperparathyroidism.

Hyperparathyroidism mainly includes primary hyperparathyroidism and secondary hyperparathyroidism.

• Primary hyperparathyroidism is most commonly caused by parathyroid adenomas, followed by multiple parathyroid hyperplasia, while parathyroid carcinoma is relatively rare.
• Secondary hyperparathyroidism is mainly caused by kidney diseases.

Who is more likely to develop fibrous cystic osteitis?

Fibrous cystic osteitis primarily occurs in advanced-stage patients with untreated hyperparathyroidism, with a slightly higher incidence in female patients than in males.

Is fibrous cystic osteitis contagious?

Fibrous cystic osteitis is not contagious.

Is fibrous cystic osteitis hereditary?

Fibrous cystic osteitis develops on the basis of hyperparathyroidism, and whether it is hereditary depends on the specific cause of hyperparathyroidism.

In some rare cases, hyperparathyroidism caused by genetic mutations may have a familial hereditary tendency.

DIAGNOSIS

How is Fibrous Cystic Osteitis Diagnosed?

When diagnosing fibrous cystic osteitis, blood tests serve as an "indicator." If blood tests reveal characteristics of hyperparathyroidism—such as high blood calcium, low blood phosphorus, and significantly elevated parathyroid hormone levels—bone-related issues that follow should raise suspicion of fibrous osteitis.

Further imaging tests (including neck ultrasound, CT, and parathyroid scintigraphy) can identify parathyroid lesions. Bone X-rays, magnetic resonance imaging (MRI), and bone scans help confirm bone abnormalities, ultimately confirming a diagnosis of fibrous cystic osteitis.

What Tests Are Needed to Diagnose Fibrous Cystic Osteitis?

Generally, blood tests and imaging examinations are required.

• Blood tests: Primarily used to confirm hyperparathyroidism, including measurements of blood calcium, phosphorus, and parathyroid hormone levels.
• Imaging tests: Mainly used to detect parathyroid lesions and identify bone abnormalities. Parathyroid lesions are typically found through neck ultrasound, CT, or parathyroid scintigraphy, often revealing parathyroid tumors. Bone abnormalities are confirmed via skeletal X-rays, MRI, or bone scans, with classic signs including decreased bone density, well-defined osteolytic destruction (often causing bone expansion), diffuse subperiosteal bone resorption, and a "salt-and-pepper" appearance in the skull. These changes primarily affect cortical bones, such as long bones in the limbs.

Which Diseases Can Fibrous Cystic Osteitis Be Easily Confused With?

Because fibrous cystic osteitis shares similarities with certain bone diseases—such as bone destruction and fractures—it can be mistaken for bone cysts, metastatic bone tumors, giant cell tumors of bone, or multiple myeloma. Doctors differentiate these conditions by testing blood calcium, phosphorus, and parathyroid hormone levels.

TREATMENT

Which department should I visit for fibrous cystic osteitis?

Endocrinology or Orthopedics.

Can fibrous cystic osteitis heal on its own?

Fibrous cystic osteitis cannot heal on its own. Immediate treatment is recommended upon diagnosis.

How is fibrous cystic osteitis treated?

Treatment for fibrous cystic osteitis includes surgical and non-surgical approaches.

• Surgical treatment: Fibrous cystic osteitis often develops from primary hyperparathyroidism. Parathyroidectomy is the preferred treatment for primary hyperparathyroidism with fibrous cystic osteitis. The surgery must ensure complete removal of the tumor and surrounding affected tissues to prevent recurrence. After successful parathyroidectomy, orthopedic surgery is usually unnecessary unless there is persistent local mass growth, severe pain affecting quality of life, fractures, or the need for fracture prevention. Orthopedic surgery can then be performed to relieve pain and stabilize or prevent fractures.
• Non-surgical treatment: Mainly involves the use of vitamin D supplements and calcium preparations.

Does fibrous cystic osteitis require hospitalization?

Fibrous cystic osteitis requires hospitalization, as most cases require prompt surgical treatment upon diagnosis.

How long is the recovery period after surgical treatment for fibrous cystic osteitis?

After surgical treatment for fibrous cystic osteitis, bone lesions gradually improve and eventually return to normal over time. Bone density typically increases three months post-surgery, with noticeable improvement in local bone conditions.

However, recovery time varies among patients depending on the severity of the condition, presence of fractures, vitamin D levels, and other factors.

Can fibrous cystic osteitis be cured?

Fibrous cystic osteitis caused by primary hyperparathyroidism can be cured with parathyroidectomy if the tumor and surrounding affected tissues are completely removed.

DIET & LIFESTYLE

What should patients with fibrous cystic osteitis pay attention to in their diet?

Due to long-term hypercalcemia, patients with fibrous cystic osteitis may experience reduced smooth muscle tone in the gastrointestinal tract and slowed peristalsis, leading to symptoms such as loss of appetite, bloating, constipation, nausea, vomiting, acid reflux, and upper abdominal pain. Some patients may also develop ulcers.

Therefore, it is recommended to eat smaller, more frequent meals and choose non-irritating, easily digestible foods that can stimulate appetite.

Additionally, a low-calcium diet should be followed, avoiding high-calcium foods such as dairy products, soy products, dried shrimp, and sesame paste to prevent excessive calcium intake and further elevation of blood calcium levels. Fresh vegetables and other fiber-rich foods should be consumed to maintain regular bowel movements.

What should patients with fibrous cystic osteitis pay attention to in daily life?

Maintaining a positive attitude is crucial for both patients and their families in the recovery process.

Patients should be encouraged to drink plenty of water—2,000 to 3,000 milliliters daily—to compensate for fluid loss due to polyuria and excessive sweating caused by hypercalciuria and hyperphosphaturia, preventing dehydration and aiding calcium excretion.

Does fibrous cystic osteitis require follow-up examinations? How are follow-ups conducted?

Yes, follow-up examinations are necessary. If there are no complications, patients should typically be re-examined at 1 month, 3 months, 1 year, and 2 years post-surgery. Follow-ups mainly include blood tests (e.g., calcium, phosphorus, and parathyroid hormone levels) and imaging of the affected bones.

What should family members of fibrous cystic osteitis patients pay attention to in daily life?

• Ensure a safe living environment to prevent falls or injuries.
• Avoid strenuous exercise and wear comfortable flat shoes.
• Use a firm mattress to reduce spinal pressure and prevent fractures.

PREVENTION

Can Fibrous Cystic Osteitis Be Prevented? How to Prevent Fibrous Cystic Osteitis?

Fibrous cystic osteitis can be prevented, primarily by early detection and treatment of hyperparathyroidism.

Individuals with a history of recurrent urinary tract stones or elevated blood calcium levels in blood tests should take these signs seriously and consider the possibility of hyperparathyroidism.