Parathyroid carcinoma (PC) is an exceptionally rare endocrine malignancy, accounting for less than 0.005% of all cancers. Severe hypercalcemia and - in larger lesions - local mass effect are common clinical presentations. Since it is often difficult to distinguish benign parathyroid adenomas from malignant parathyroid lesions by imaging, postoperative histological confirmation of invasive characteristics, supported by immunohistochemical markers, is necessary. The 2022 WHO classification integrates histological and molecular characteristics to enhance diagnostic accuracy. Recent advances in imaging have significantly improved detection, localization, and staging. In nuclear medicine, [18F]FDG PET/CT or PET/MR contributes to identifying metabolically active disease, particularly in recurrent or metastatic settings. The role of [18F]fluorocholine PET/CT or PET/MR in parathyroid carcinoma is yet to be defined; however, recent reports suggest potential particularly in the localization of abnormal PTH sources. Computed tomography (CT) offers detailed anatomical information for surgical planning and can be augmented with local perfusion information (4D-CT) for detecting enhancing parathyroid tissue. Surgery remains the primary treatment modality, even in metastatic cases, following comprehensive imaging-based staging and appropriate management of hypercalcemia. External beam radiation therapy is used in lesions not amenable to surgical removal. Targeted treatments, such as tyrosine kinase inhibitors, temozolomide, and immune checkpoint inhibitors, have demonstrated potential benefits in specific patient subsets, despite the absence of standardized guidelines for systemic therapy in PC. This chapter examines the existing literature on parathyroid carcinoma, with particular emphasis on the critical role of nuclear medicine and radiological imaging in its diagnosis, staging, and therapeutic management.