Figure 12b. Malignant schwannoma. (a) US image demonstrates a 1.3 x 1-cm heterogeneous mass (arrow) that involves the scrotal wall. The mass is hypoechoic internally and more echogenic peripherally. T = testicle. (b) Photograph of the gross specimen of a schwannoma that was removed from a 79-year-old man shows a pink-tan, rubbery, sharply circumscribed tumor. Scale is in centimeters.