Case of parathyroid carcinoma with a highly aggressive clinical course.

We describe a 59-year-old woman who presented with pathological osteoporosis, cerebral infarction, hypercalcemia, and markedly high parathyroid hormone levels. The diagnosis was primary hyperparathyroidism, and parathyroidectomy was performed. Histopathological examination showed parathyroid adenoma. Surgical exploration for recurrent parathyroid carcinoma was undertaken at 2 and 3 years after the initial neck resection. Pulmonary metastasis was diagnosed at 4 years after the initial surgery.Despite treatment with intravenous bisphosphonates, her calcium and parathyroid hormone (PTH) levels remained elevated, and leg amputation was performed following the development of arteriosclerosis obliterans at 6 years after the initial neck resection. The prognosis for parathyroid carcinoma is often difficult to predict due to recurrence.