Pathological fracture following minimal trauma as the initial presentation of parathyroid carcinoma-associated hyperparathyroidism in a young man: a case report.

Background: Parathyroid carcinoma (PC) is a rare malignant endocrine tumor, accounting for approximately 0.005% of all malignancies and representing an uncommon cause of primary hyperparathyroidism. Excessive secretion of parathyroid hormone leads to severe hypercalcemia, resulting in multisystem complications, including skeletal fragility, nephrolithiasis, neuromuscular manifestations, and cardiovascular and neurocognitive disturbances. Preoperative diagnosis remains challenging, as PC frequently mimics benign parathyroid disease both clinically and radiologically. Case presentation: A 36-year-old man sustained a pathological fracture of the right radius during routine boxing training following minimal trauma. His medical history was notable for recurrent nephrolithiasis over the preceding six years, requiring multiple bilateral pyeloplasties, as well as several previously documented episodes of hypercalcemia of unknown etiology. Preoperative laboratory evaluation revealed severe hypercalcemia (4.0 mmol/L; reference range 2.2-2.7) and markedly elevated parathyroid hormone levels (2145 ng/L; reference range 15-65), consistent with primary hyperparathyroidism. Further endocrinological evaluation and imaging identified a parathyroid tumor. Surgical resection was performed, and histopathological examination confirmed the diagnosis of parathyroid carcinoma. Conclusion: This case highlights a pathological fracture following minimal trauma as the initial manifestation of parathyroid carcinoma-associated hyperparathyroidism in a young adult. It underscores the importance of considering endocrine etiologies in patients presenting with pathological fractures and unexplained hypercalcemia to enable timely diagnosis and appropriate management.