THE MANY FACES OF PARATHYROID CARCINOMA

A CASE SERIES

Abstract

INTRODUCTION
Parathyroid carcinoma is rare, affecting less than 1% of patients with primary hyperparathyroidism (PHPT). Parathyroid carcinoma with concomitant papillary thyroid carcinoma is also rare, and the etiology is not fully defined.

CASE
We present 3 patients with parathyroid carcinoma and discuss their presenting symptoms, characteristics, and treatment. Two women and 1 man (2 Filipinos and 1 Marshallese) ages 53-68 years old had parathyroid carcinoma. Two had primary hyperparathyroidism, one had non-functioning type of parathyroid carcinoma. Two had concomitant bone or renal disease. All three had concurrent thyroid disease- 2 had papillary thyroid microcarcinoma, one had colloid goiter. Because each one had different indications for neck surgery, different surgical techniques were done. Parathyroid cancer sizes ranged from 2.0-5.2 cm, with capsular and vascular invasion in all three. One case had double parathyroid carcinomas. On follow-up, the patient with the largest tumor size had tumor recurrence within 1 year from surgery.

CONCLUSION
This case series, to the best of our knowledge, includes the first reported case of synchronous parathyroid carcinoma and papillary thyroid carcinoma in a Marshallese patient, as well as the 7th case of double parathyroid carcinomas. Parathyroid carcinoma is a rare condition, and coupled with its highly variable presentation, as seen in the 3 cases, presents clinicians with a difficulty in arriving at a diagnosis. Histopathology remains the gold standard in diagnosis and is a key in guiding management. Since coexisting thyroid and parathyroid disease may occur, thyroid pathology should be evaluated in the presence of PHPT.