Primitive neuroectodermal tumor of the prostate in a 58-year-old man: A case report

Figure 1 Preoperative pelvic imaging. A: Contrast-enhanced computed tomography shows a large, cystic-solid mass in the pelvis; B and C: At magnetic resonance imaging (MRI), the lesion near the prostate is isointense to slightly hyperintense on T1-weighted imaging (WI), with heterogeneous intensity on T2WI; D and E: There is heterogeneous hyperintensity on diffusion-WI with opposing hypointensity on the apparent diffusion coefficient maps; F-H: The solid part is enhanced during the arterial phase on contrast-enhanced MRI, with persistent enhancement in the venous and delayed phases. No enhancement is seen in the cystic part.

Figure 2 Post-operative contrast-enhanced pelvic computed tomography. Imaging after the first cycle of chemotherapy at 2 mo postoperatively shows no obvious signs of residual tumor or recurrence.

Figure 3 Hematoxylin-eosin and immunohistochemical staining. A: Hematoxylin-eosin staining reveals small round cells arranged closely in a flaky pattern (× 200); B: Immunohistochemical staining of the small round cells for CD99 shows strong positivity for this marker (× 200); C and D: Immunohistochemical staining for vimentin and synaptophysin is positive (× 200).