What is brown tumor?

Brown tumor, also known as osteitis fibrosa cystica, is a benign bone lesion that is commonly seen in patients with hyperparathyroidism, particularly primary hyperparathyroidism. It is a result of excessive secretion of parathyroid hormone (PTH) from the parathyroid glands, which leads to increased bone resorption and disruption of normal bone metabolism.

Brown tumors are characterized by the replacement of normal bone tissue with fibrous connective tissue and the presence of giant multinucleated osteoclasts, which are cells responsible for bone resorption. These tumors can occur in various bones throughout the body, but they are most commonly found in the jaws, long bones, ribs, and pelvis.

Clinically, brown tumors can manifest with localized bone pain, swelling, and tenderness. In severe cases, they can cause bone deformities, fractures, and pathologic fractures.

Brown tumors are typically diagnosed based on clinical features, radiological findings, and laboratory tests. X-rays and other imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), can reveal the presence of lytic bone lesions with a cystic or expansile appearance. Laboratory tests, including serum calcium and PTH levels, are performed to confirm the underlying hyperparathyroidism.

Treatment for brown tumors involves addressing the underlying hyperparathyroidism. The primary treatment is surgical removal of the overactive parathyroid gland or glands, which usually leads to resolution or improvement of the brown tumors. In some cases, medications may be prescribed to lower calcium levels and inhibit bone resorption.

If brown tumors cause significant symptoms or complications, such as bone deformities or fractures, additional treatments may be necessary. These may include surgical interventions, such as curettage or bone grafting, to repair bone damage.