Spectrum of neurogenic tumors in the thorax: CT and pathologic findings

Neurilemomas and neurofibromas appear as round soft tissue masses at CT. Va riable enhancement with either homogeneity or heterogeneity is seen in neur ilemomas. Attenuation of the tumors on enhanced CT depends on histology: th e extent of Antoni A or B tissue and the amount of myxoid or cystic degener ation or hemorrhage. Neurofibromas are usually homogeneous low attenuation lesions on unenhanced CT. They show homogeneous enhancement or early centra l blush on enhanced scan. The extent of enhancement depends on the proporti ons of tumor components: nerve sheath cells, collagen bundles, and areas of myxoid degeneration. Malignant nerve sheath tumors show variable attenuati on. Bony destruction, pleural effusion, and metastatic pulmonary nodules ma y also occur. Ganglioneuromas appear as oblong homogeneous low attenuation lesions on both enhanced and unenhanced CT. This low attenuation is due to their pathologic components, with an abundant amount of myxoid matrices and a relatively small amount of ganglion cells. Neuroblastomas appear as aggr essive soft tissue lesions with calcification. Ganglioneuroblastomas may ap pear with features in between those of ganglioneuromas and neuroblastomas. The typical location of the posterior mediastinum or the aortopulmonary win dow and high enhancement with administration of contrast medium at CT sugge st the diagnosis of paragangliomas.