Parathyroid carcinoma: clinical presentation and treatment.

Parathyroid tumors account for only a small percentage of all head and neck neoplasms. The overwhelming majority of these are parathyroid adenomas that result in primary hyperparathyroidism. From 0.5% to 4% of hyperparathyroid patients, however, will be found to have a parathyroid carcinoma. In this paper, the authors relate their recent experience with such a patient and with two other such cases. Parathyroid carcinoma patients usually present with striking hyperparathyroidism and hypercalcemia, with the resultant related symptoms being more severe than those associated with parathyroid adenomas. Parathyroid carcinomas also tend to be large and may be detectable by current imaging techniques. The surgical appearance of these lesions is also distinct; the tumors are frequently multilobulated, gray-tan in color, quite firm, and often invasive. These physical findings are important since frozen section diagnosis may be difficult. The final histologic diagnosis depends on the presence of mitotic figures and capsular and vascular invasions. Preoperative medical problems, surgical approach, and prognostic factors are also discussed.