Osteitis fibrosa cystica masquerading as bone neoplasm

Large parathyroid adenomas: Potential mechanisms to reconcile adenoma size and disease phenotype

Parathyroid adenomas weighing more than 3.5 g are reported variously as "atypical", "large" or "giant" parathyroid adenomas. All such adenomas are rare variants accounting for no more than 1.5% of all parathyroid adenomas. Large parathyroid adenomas are often associated with more severe form of the disease, including osteitis fibrosa cystica (OFC) and share many biochemical, histological, and molecular features of both benign and malignant parathyroid neoplasms, and are considered a distinct clinical entity. However, the pathogenesis of oversized parathyroid adenomas and the often-associated skeletal phenotype remains unclear. We present 5 cases of primary hyperparathyroidism (PHPT) with OFC, an uncommon manifestation of contemporary PHPT, associated with larger parathyroid adenomas, seen in the Bone and Mineral Disorders Clinic of the Henry Ford Health in the last 30 years to illustrate the critical role of vitamin D nutrition in the pathogenesis of both the OFC and adenoma size. The estimated prevalence of OFC was very low 0.2%, 5 of the >3000 surgically confirmed cases of PHPT seen during this time. The mean ± SD values were: age: 36.8 ± 22.1 years (4 of the 5 <36years), serum calcium 11.6 ± 1.1 mg/dl, alkaline phosphatase 799 ± 487 IU/L, PTH 1440 ± 477 pg/ml, 25-hydroxyvitamin D 13.0 ± 8.9 ng/ml, 1,25-dihyroxyvitamin D 26.5 ± 13.7 pg/ml, urine calcium 562 ± 274 mg/day, and parathyroid adenoma weight 4.53 ± 2.2 g. Parathyroidectomy led to the resolution of both the biochemical indices and OFC in each patient without recurrence over >10 years of follow-up. Because OFC is a very rare in the West, but very common areas of endemic vitamin D deficiency, we also examined the relationship between vitamin D nutrition, as assessed by serum 25-hydroxyvitamin D level, and parathyroid adenoma weight as well as prevalence of OFC in two large secularly diverse cohorts of patients with PHPT (Detroit, USA and Chandigarh, India). Based on this relationship and the relative prevalence of OFC in these two large cohorts, we propose that vitamin D nutrition (and perhaps calcium nutrition) best explains both the adenoma size and prevalence of OFC.

Osteitis fibrosa cystica mimicking bone tumor, a case report

Background

We report a case of osteitis fibrosa cystica, a rare benign resorptive bone lesion caused by hyperparathyroidism, that presented on imaging as an aggressive bone tumor.

Case presentation

The patient is a 51-year-old male complaining of severe sustained pain of the right hip region. Imaging studies were suspicious for a malignant tumor of the right iliac bone. Biopsy under CT guidance was performed and showed remodeled bone trabeculae with numerous osteoclasts, excluding bone tumor and raising the possibility of osteitis fibrosa cystica. Complementary tests disclosed elevated blood level of parathyroid hormone and a partially cystic enlarged left inferior parathyroid gland consistent with adenoma. After parathyroidectomy, the clinical symptoms were relieved and the radiological findings were significantly improved, which confirmed the diagnosis.

Conclusions

Metabolic diseases-associated bone lesions should always be considered in the differential diagnosis of bone tumors, to avoid unnecessary surgeries and treatments.

Multiple Brown tumors in a Case of Primary Hyperparathyroidism with Pathological Fracture in Femur

INTRODUCTION

Pathological fractures in long bones are commonly caused by simple bone cyst or Osteogenesis imperfecta in children and by metastatic tumors from primary carcinoma, multiple myeloma, osteoporosis, and bone tumors in adults. Hyperparathyroidism causing pathological fractures, though a well-known entity, is seen infrequently in clinical practice. The fractures occur in the expansile fibro-cystic bone lesions called as "Brown tumor." The reported case describes a patient with classical features of primary hyperparathyroidism (PHPT) having multiple lytic lesions in pelvis and bilateral femur with pathological fracture. It is being reported due to its rarity.

CASE REPORT

A 28-year-old young married lady presented with chronic dull aching pain in both thighs and difficulty in walking for 2 years. Examination revealed tenderness in both thighs, with antalgic gait. X-ray pelvis with both thighs showed multiple lytic lesions of variable size in both femora and pelvis. Blood investigations showed raised levels of serum calcium, with highly raised levels of serum parathyroid hormone (PTH). Contrast-enhanced computerized tomography (CT) scan of neck demonstrated parathyroid adenoma. The patient admitted for prophylactic nailing for right femur, developed a fracture while indoor and was managed by right proximal femoral nailing, followed by parathyroid adenoma excision. Follow-up showed dramatic clinical and radiological improvement with good healing of fracture. Lytic lesions healed gradually and blood parameters returned to normal. The patient remains asymptomatic at 2 years follow-up.

CONCLUSION

Advanced case of symptomatic PHPT affecting bones is rare and it should be considered as a differential diagnosis in cases of a solitary and or multiple osteolytic lesions. Serum calcium and PTH level estimation at an early stage prevents missing the diagnosis and progression of disease. Early diagnosis and appropriate treatment help in rapid clinical improvement with almost total reversal of bony changes, thus avoiding devastating complications.