MRI and pathological findings in two cases of Askin tumors.

Askin tumors are primitive peripheral neuroectodermal tumors (PPNET) located in the thoracopulmonary region. This entity was first proposed in 1979 by Askin et al. These highly malignant tumors occur primarily in children and young adults. Pre- und postoperative MRI findings are presented for two pathologically proven cases. MRI is the most appropriate imaging modality for the diagnosis and eventual follow-up for these tumors. They appear homogenous, and iso- or discretely hypointense in comparison to the spinal cord on T1-weighted images and hyperintense on proton density and T2-weighted images. They show a very stark contrast enhancement after i.v. injection of paramagnetic contrast agents. Sharp tissue borders, and exact tumor extension were shown in both cases. The high signal intensity on T2-weighted images was not altered by chemotherapy.