Introduction: Parathyroid carcinomas are very rare tumors and may arise in the normally located or ectopic gland. The latter present certain diagnostic difficulties, and there are no specific guidelines on their management. We present a case of parathyroid carcinoma arising within an ectopically located intrathyroid gland and discuss the diagnosis, management, and difficulties encountered. Furthermore, we review all six previously reported cases of this rare event and demonstrate the patterns in presentation, as well as the differences in management.