Parathyroid carcinoma: Report of 10 patients and literature review.

Objective: Parathyroid carcinoma (PC) is a rare disease with high rates of misdiagnosis and recurrence. This report summarized the clinical and pathological characteristics of 10 patients with PC at our hospital, to improve the early recognition and prognosis of PC.

Methods: The clinical manifestations, imaging findings, pathological features, treatments, and prognostic data of 10 patients diagnosed with PC at the First Medical Center, Chinese PLA General Hospital from 2003 to 2021 were analyzed.

Results: There were 7 male and 3 female patients with PC whose average age was 41.4 ± 9.4 years. All patients had bone involvement (bone pain and/or osteoporosis), meanwhile 6 patients had kidney stones and 7 patients had palpable neck masses. Five patients presented with tumor metastasis, invading lymph nodes, lung, liver, or bone. Laboratory examinations revealed elevated serum total calcium (4.15 ± 0.81 mmol/L), parathyroid hormone (PTH, 1236.1 ± 519.9 pg/mL) and alkaline phosphatase (405.8 ± 219.0 IU/L) levels. Especially, hypercalcemic crisis occurred in 9 patients. The diagnosis of PC depended on histopathological features of the parathyroid tumor, including capsular and/or vascular invasion. All patients underwent at least en bloc resection. In the follow-up, six patients with relatively high preoperative PTH levels (1519.5 ± 436.8 pg/mL) relapsed postoperatively. Two patients with the Ki-67 index ≥ 10% in parathyroid tumor tissue and distant metastasis died within 2 years after the operation.

Conclusion: Severe bone pain, kidney stones, hypercalcemic crisis, and markedly elevated PTH usually indicate PC. A markedly elevated PTH level, tumor metastasis, and the Ki-67 index ≥ 10% may be indicators of poor prognosis.