Parathyroid carcinoma with multiple brown tumors and pathological fracture: case report

Abstract

Introduction: Parathyroid carcinoma is a rare endocrine neoplasia that accounts for less than 1% of cases of primary hyperparathyroidism and usually presents with severe hypercalcemia and bone involvement. Clinical case: A 27-year-old male patient was referred for persistent pain in his right knee, exacerbated by minor trauma. Radiographic studies identified a pathological fracture and multiple osteolytic lesions. Biochemical analyses showed severe hypercalcemia (16.9 mg/dL), acute renal failure, and electrolyte disturbances. A bone biopsy reported a brown tumor, and a parathyroid scan revealed an ectopic mediastinal adenoma. The parathyroid adenoma was resected, and immunohistochemical analysis showed vascular permeation with a positive CD31 staining, confirming parathyroid carcinoma. The patient underwent complementary hemithyroidectomy, orthopedic treatment with tumor dissection, cementation, and internal fixation, along with zoledronic acid. The patient is currently being monitored without clinical or biochemical recurrence. Conclusion: This case highlights the importance of considering parathyroid carcinoma in young patients with severe hypercalcemia and multiple bone lesions. Immunohistochemistry is essential to confirm malignancy and determine surgical treatment. Comprehensive multidisciplinary management reduces complications, controls hypercalcemia, and improves prognosis.