Primitive neuroectodermal tumor arising in the abdominopelvic region: CT features and pathology characteristics

We analyze the computed tomography (CT) findings of a peripheral primitive neuroectodermal tumor (pPNET) arising in the abdominopelvic cavity and to improve understanding of the CT images of the tumor. Twelve cases of pPNET confirmed by histopathology were analyzed retrospectively. Image characteristics of CT scanning were analyzed and compared with the pathology of the tumors. There were 8 males and 4 females with mean age of 34.5 years. Unenhanced CT images showed large heterogeneous and ill-defined or well-defined masses with multiple patchy hypodense areas. The average diameter was 9.8 cm (range 4.0-17.2 cm). Contrast-enhanced CT images showed variable heterogeneous contrast enhancement with multiple non-enhancement areas. 3 cases revealed metastasis and 4 cases invaded into adjacent organs. Pathology showed areas of degeneration and necrosis in all tumors. Cluster of differentiation 99 and neurone specific enolase were detected positive in 11 and 12 cases, respectively. In conclusion, pPNET in the abdominopelvic cavity likely affects young adults with a slight male preponderance and tend to be large and aggressive. Although CT findings are nonspecific and variable, a large ill-defined or well-defined heterogeneous mass with multiple patchy hypodense areas reflecting their cystic degeneration and necrosis on pathology examination may suggest the diagnosis of pPNET.