Radiologic Evaluation of Thoracic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) of the thorax comprise a spectrum of pulmonary and mediastinal tumors ranging from well-differentiated, indolent lesions to highly aggressive carcinomas. Imaging, especially computed tomography and positron emission tomography, plays a central role in noninvasive tumor detection, characterization, staging, and treatment planning. Diagnosis of thoracic NENs prior to definitive histopathology is challenging, owing to their variable and often nonspecific imaging appearance, as well as the exceptional rarity of several subtypes. Because these tumors are often discovered incidentally, delayed diagnosis is common. This review provides an overview of pulmonary and mediastinal NENs, including typical and atypical carcinoids, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, large-cell neuroendocrine carcinoma, small-cell lung carcinoma, thymic NENs, paragangliomas, and metastatic NENs. Furthermore, pulmonary NENs may occur in association with syndromic conditions characterized by multiple neoplasms, such as multiple endocrine neoplasia and succinate dehydrogenase deficiency. Case examples of thoracic NENs are integrated with their characteristic imaging, clinical, and pathological features to facilitate more accurate and confident diagnosis of these rare tumors.