Brown Tumor Locations in Hyperparathyroidism
Brown tumors most commonly affect the ribs, clavicle, long bones, and pelvic girdle, though they can occur in the mandible, maxilla, and rarely the spine. 1, 2
Most Common Skeletal Sites
Brown tumors are non-neoplastic, reparative cellular processes resulting from chronic parathyroid hormone excess, and their distribution follows a predictable pattern:
Primary Sites (Most Frequent)
- Ribs - among the most commonly affected sites 1, 3
- Clavicle - frequently involved 1, 3
- Long bones - common location for these lesions 1, 2
- Pelvic girdle/bones - regularly affected 1, 3
Craniofacial Involvement
- Mandible - the most common facial bone affected 1, 4, 3
- Maxilla - less common than mandible but well-documented 1, 4, 3
- Maxillary sinus - can present as isolated lesions filling the sinus cavity 1, 3
Important clinical note: Solitary maxillary brown tumors as initial presentation are rare; facial brown tumors are typically accompanied by involvement of other facial bones. 1
Uncommon Sites
- Cervical spine - extremely rare with only 11 cases reported in the literature as of 2018 5
- Axial skeleton - can involve vertebrae with risk of spinal cord compression 2, 5
- Peripheral trunk - documented in multiple bone tumor presentations 2
Clinical Presentation Patterns
Distribution Characteristics
- Brown tumors can present as solitary lesions (particularly in the maxilla or mandible) or as multiple lesions affecting both axial and peripheral skeleton 1, 4, 2
- When multiple brown tumors are present, they typically involve a combination of the common sites listed above 2
Critical Diagnostic Consideration
Brown tumors must be distinguished from ossifying fibromas of the jaw, which occur in CDC73-related Hyperparathyroid-Jaw Tumor Syndrome - these are distinct entities, not the same as brown tumors of hyperparathyroidism. 6
Diagnostic Approach for Suspected Brown Tumors
When evaluating a bone lesion that may represent a brown tumor:
- Obtain serum calcium and parathyroid hormone levels - essential to establish underlying hyperparathyroidism 6, 1
- Perform cross-sectional imaging (CT/MRI) to assess extent and identify additional lesions 2
- Consider biopsy if diagnosis is uncertain, as brown tumors are frequently misdiagnosed as malignancy 1, 4
Common Pitfall
Brown tumors tend to be misdiagnosed as malignant bone lesions, leading to delayed diagnosis of underlying hyperparathyroidism - this is particularly problematic in young women who have higher probability of developing brown tumors. 1, 4
Management Implications by Location
Facial/Jaw Lesions
Direct surgical excision may be indicated for maxillary or mandibular brown tumors to prevent facial deformity and orbital compression, even though most brown tumors regress spontaneously after parathyroidectomy. 1
Spinal Lesions
Cervical spine brown tumors require neurosurgical management with corpectomy to promote spinal stability and decompress neural structures, preventing neurological deficits despite the benign nature of the lesion. 5
General Approach
Most brown tumors at other sites show spontaneous regression following successful treatment of the underlying hyperparathyroidism with parathyroidectomy. 1, 4