When signs are silent: coexisting parathyroid adenoma and papillary thyroid carcinoma without hyperparathyroidism

Parathyroid adenomas are benign neoplasms of the parathyroid parenchymal cells and the most common cause of primary hyperparathyroidism. The existing literature reporting data on parathyroid adenomas without elevated parathormone and calcium levels is, to our knowledge, limited. The aim of this article is to describe such a case in a patient with coexistent papillary thyroid carcinoma. A 54-year-old female patient presented with a nontoxic multinodular goitre, a nodular lesion in the thyroid isthmus classified as Bethesda V and a lesion behind the left upper thyroid lobe, indicative of parathyroid tumour. There was no clinical or laboratory evidence of hyperparathyroidism. Total thyroidectomy and left upper parathyroidectomy were performed and the histological confirmation of parathyroid adenoma was obtained. This article constitutes a rare case report of a parathyroid adenoma with synchronous papillary thyroid carcinoma but without the expected clinical and laboratory findings of hyperparathyroidism.