INTRODUCTIONParathyroid carcinoma (PC) is a rare endocrine cancer [1,3] and the most uncommon cause of primary hyperparathyroidism (pHPT). It usually induces elevated serum calcium and parathyroid hormone (PTH) levels and the clinical presentation is often characterized by severe symptoms of hypercalcaemia. The diagnosis is not always immediate, especially if there is no evidence of a neck mass which may suggest this kind of disease.The aim of this work is to describe the peculiar clinical presentation of a case of PC and to highlight the importance of suspecting a malignant parathyroid disease in the presence of a pHPT associated with peculiar biochemical and clinical features. The suspicion is essential to perform an adequate intervention at first surgical approach, as which affects the subsequent prognosis.