Variability of clinical presentations in three cases of parathyroid carcinoma.

Parathyroid carcinoma accounts for 0.5 to 4.0% of cases of primary hyperparathyroidism. The prognosis depends largely on the extent of successful resection at the time of initial operation. Therefore, early diagnosis before surgery is important. We report 3 cases of primary hyperparathyroidism. The first patient, a 20-year-old uremic female, had refractory hypercalcemia after 5 years of hemodialysis treatment. Hypercalcemia persisted despite repeated parathyroidectomy. Pathology revealed diffuse hyperplasia of the parathyroid glands with focal adenomatous changes. Multiple pulmonary metastases were found later. The second patient, a 45-year-old female with history of nephrolithiasis, presented with severe osteoporosis. She underwent repeated parathyroidectomy for local recurrence. Pathology disclosed typical features of parathyroid carcinoma with adjacent lymph node metastasis. The third patient, a 34-year-old male, had recurrent episodes of extremity fracture and hypercalcemia with palpable neck mass. He underwent resection of the parathyroid tumor. Vascular and capsular invasions were noted microscopically. All three patients were relatively young and had extremely high intact parathyroid hormone (iPTH) level (15 to 31 times the upper limit of normal). The first patient died of hypercalcemia and respiratory failure and the other 2 were treated successfully with surgical excision and, in case 2, combined chemotherapy and radiotherapy. The latter 2 patients had no recurrence during 18 months and 14 months of follow-up, respectively. Our experience with these cases suggests that the combination of the following characteristics are highly suggestive of parathyroid carcinoma: young age, palpable neck mass, concomitant renal and skeletal disease, and extremely high iPTH level in patients with PTH-dependent hypercalcemia.