Parathyroid carcinoma is a rare endocrine malignancy with an indolent course but a high risk of recurrence. Diagnosis remains challenging, requiring integration of clinical, biochemical, radiologic, and histopathologic findings. We report a young patient presenting with primary hyperparathyroidism complicated by multiple pathologic fractures and chronic renal failure. Despite initial surgical and medical management, late aggressive recurrence occurred, resulting in significant systemic complications. This case highlights the need for vigilant long-term surveillance and improved diagnostic and therapeutic strategies.