Pathological subtrochanteric fracture revealing a primary hyperparathyroidism: A case report

Introduction: Primary hyperparathyroidism is the third most common endocrine disorder after diabetes and thyroid disease. Nevertheless, a pathological fracture revealing primary hyperparathyroidism is not commonly described.Case presentation: We present the case of a 30-year-old male patient who was admitted with a subtrochanteric pathologic fracture of her left femur after a trivial fall. Due to suspicion of bone metastases, a thoraco-abdominopelvic CT scan was requested. It revealed multiple irregular circumscribed lytic bone lesions in the ribs, the right scapula, the dorsal spine, and the pelvic girdle; bilateral renal lithiasis; and a nodule contiguous to the left posterior thyroid lobe. A surgical biopsy of the bone lesion was performed. Histopathological examination confirmed the diagnosis of primary hyperparathyroidism with a brown tumor. Laboratory tests showed increased both calcium and PTH levels. The patient underwent cephalomedullary nail fixation with bipolar locking. After that, a parathyroidectomy was performed. At six months' follow-up, the functional result was satisfactory.Clinical discussion: Primary hyperparathyroidism is the most common cause of hypercalcemia. It occurs as a result of a parathyroid adenoma in 80 % of cases. Definitive diagnosis should be made by clinical history, radiological findings and confirmed by biochemical tests including serum parathyroid hormone (PTH), alkaline phosphatase, calcium, phosphate, and vitamin D levels. Conclusion: This case report emphasizes the need of including brown tumors in the differential diagnosis of multifocal osteolytic bone lesions, in order to ensure appropriate treatment.