Brown Tumor: Rare Today, but Never to Be Forgotten
https://doi.org/10.15605/jafes.041.S1
- Author:
Min Jing Choo
1
;
Liang Wei Wong
2
Author Information
1. Department of Internal Medicine, Hospital Kulim; Department of Internal Medicine, Hospital Taiping
2. Unit of Endocrinology, Endocrine Institute
- Publication Type:Journal Article
- MeSH:
Neoplasms
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):77-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Brown tumors are rare skeletal manifestations of primary
hyperparathyroidism (PHPT), now seen in less than 5%
of cases due to widely accessible biochemical screening.
Despite being benign, they can mimic malignant bone
lesions, making diagnosis challenging.
Case:A 45-year-old female presented with lethargy and
hypercalcemia (corrected calcium 3.5 mmol/L) and was
discharged after intravenous zoledronate. She returned
1 week later with an enlarging gingival mass present
for 2 months but not previously disclosed, with a strong
family history of malignancy. Examination revealed a 6
× 3 cm pedunculated lesion over the right alveolar ridge.
Biochemistry showed persistent hypercalcemia (2.7–2.9
mmol/L), hypophosphatemia, and elevated alkaline
phosphatase. Contrast-enhanced computed tomography of
the neck demonstrated lytic mandibular and skull changes,
raising suspicion for malignancy. Tumor markers and
multiple myeloma screening were negative. Parathyroid
hormone (PTH) later returned markedly elevated at 222.1
pg/mL (upper limit of normal 56.9 pg/mL), consistent
with PHPT, alongside concomitant vitamin D deficiency.
Excision biopsy of the mandibular lesion confirmed a
brown tumor on histopathology. Following preoperative
localization, she underwent left parathyroidectomy and
recovered without hungry bone syndrome. Histology
confirmed a parathyroid adenoma, and she has remained
normocalcemic since.
Brown tumors arise from prolonged osteoclastic activity
and represent advanced PHPT. Craniofacial involvement
is rare, with the mandible affected in 4–5% of cases,
and lesions may clinically and radiologically mimic
primary bone tumors or metastases, creating diagnostic
uncertainty. Hypercalcemia should be systematically
investigated to determine the underlying cause, with early
measurement of PTH to distinguish PTH-dependent from
PTH-independent etiologies. Untreated brown tumors
may result in bone pain, deformity, pathological fractures,
and functional impairment, highlighting the importance
of early detection and management.
Conclusion:Brown tumors, although rare, remain an important
differential diagnosis for lytic bone lesions in the context
of hypercalcemia. Early measurement of PTH and careful
clinical examination are essential to avoid misdiagnosis
and prevent disease-related morbidity.
- Full text:2026080411212666977EP_A105.pdf
