Metastatic parathyroid carcinoma presenting as an osteolytic cervical vertebral mass 5 years after parathyroidectomy

Abstract

Introduction: Parathyroid carcinoma is a rare malignancy that is challenging to diagnose, with metastasis regarded as the only true way to differentiate parathyroid carcinoma from adenoma. Case presentation: A 63 year-old woman presented to the emergency department with neck and right arm pain. She reported a previous parathyroidectomy for a mediastinal parathyroid adenoma. Admission labs showed hypercalcemia (serum calcium 13; ionized calcium 1.47; PTH 138.5). MRI-spine revealed a soft tissue mass causing destruction of the C4 vertebral body and spinal cord compression. Sestamibi showed intense tracer uptake in the vertebral mass with nonfocal physiologic thyroidal uptake. Otolaryngology was consulted to assist in the approach to the cervical spine lesion as well as address the hypercalcemia. Intraoperatively, the vertebral mass was exposed and resected; frozen section revealed hypercellular parathyroid and PTH dropped from 138.5 to 9.1. Discussion: Parathyroid carcinoma typically presents with comorbidities due to hypercalcemia. Novelties from the case, including the unusual presentation with spinal cord compression, are discussed. Keywords: Parathyroidectomy, Parathyroid glands, Malignancy, Metastasis, Cervical spine