Parathyroid Carcinoma: A Rare Endocrine Malignancy.

BACKGROUND Parathyroid carcinoma (PC) is an extremely rare endocrine malignancy, with a reported increase in incidence in the past decade. PC generally presents in an indolent fashion, featuring nonspecific symptoms associated with hypercalcemia. CASE REPORT Case 1: A 30-year-old man was admitted for symptoms associated with hypercalcemia and elevated parathyroid hormone (PTH). Imaging examinations showed the presence of a cervical nodular lesion. The patient underwent surgery, and the pathological diagnosis was PC. Case 2: A 45-year-old man with a history of hypothyroidism was referred to our Endocrinology Department for a cervical nodular lesion. A fine-needle aspiration was performed, and the result was suggestive of papillary carcinoma. Blood testing showed only mild hypercalcemia and PTH elevation, with no associated symptoms. The patient underwent surgery, and the histological examination confirmed the diagnosis of PC. Case 3: A 38-year-old man presented with diffuse bone pain and muscle weakness, severe hypercalcemia, high levels of PTH, and a cervical mass. The patient underwent surgery. Diagnostic pathology confirmed the diagnosis of PC. Five years later, the patient presented with a cutaneous metastasis, followed 1 year later by pulmonary metastases. CONCLUSIONS Most PCs are slow-growing tumors. Some of these tumors are diagnosed in association with hereditary syndromes. A clear distinction between benign and malignant lesions is not always simple because there is a lack of specific clinical distinguishing features of malignant lesions. Currently, surgical resection is the preferred approach; however, owing to the rarity of this condition, there is a void of high-quality data.