Primitive neuroectodermal tumors of the abdominal wall and vulva in children: Report of two cases and review of the literature

Figure 1 Computed tomography evaluation of Case 1. A: Axial computed tomography image showing a fusiform soft tissue density between the abdominis obliquus internus musculus and the abdominal transverse muscle in the right inferior abdomen; the middle of the mass has irregular patchy calcification; B: Enhanced image showing uniform enhancement of the mass; C and D: The mass involving the musculus transversus abdominis.

Figure 2 Computed tomography evaluation of Case 2. A: Axial computed tomography image showing an irregular soft tissue density in the vagina; B: Enhanced image showing non-uniform lesion enhancement; C: Sagittal image showing partial lesion protruding into the vagina.

Figure 3 Case 1. A and B: Small round cells with large nuclei and little cytoplasm showing the characteristic perivascular rosette of primitive neuroectodermal tumors (H and E, 100× and 200×); C: Tumor cells positive for CD99 (DAB, 200×); D: Diffuse staining for Syn (DAB, 200×).

Figure 4 Fluorescent in situ hybridization in Case 1. The 5'-terminus of the EWSR1 gene was labeled with red dye, and the 3'-terminus labeled with green dye. Results showed that the red and green signals were isolated from tumor cells, suggesting translocation of the EWSR1 gene (DAPI, 1000×).

Figure 5 Fluorescent in situ hybridization in Case 2. The separation of the red and green signals indicates that the EWSR1 gene is translocated. Red arrows indicate the translocation change of the EWSR1 gene (DAPI, 1000×).