What are the cross sectional imaging features of testicular cancer?
On cross-sectional imaging, an intratesticular mass is seen with increased blood flow on Doppler US and enhancement on CT and MRI. Seminoma is typically homogeneous, with hypoechogenicity on US and intermediate T1-weighted and low T2-weighted signal intensity on MRI relative to testicular parenchyma ( Figure 39-11 ). In contradistinction, nonseminomatous germ cell tumor is typically heterogeneous in appearance with variable echogenicity and signal intensity secondary to hemorrhage, cystic change, necrosis, fat, calcification, and/or fibrosis ( Figure 39-12 ). Extratesticular extension and invasion of adjacent structures may sometimes be seen with testicular cancer. Regional lymphadenopathy and distant metastatic disease (most often to nonregional lymph nodes, lung, liver, brain, and bone marrow) may also be present.