Figure 1. Seminoma. The appearance is unusual because of the presence of numerous pseudoglandular formations and cords. Additionally, the fibrous septa do not have the typical sprinkling of lymphocytes seen in the more typical seminoma.
Figure 2. Spermatocytic seminoma. There is conspicuous edema in the background, a picture that may be a clue to the diagnosis on low-power examination, albeit it is not diagnostic.
Figure 3. Leydig cell tumor. Focal conspicuous cysts are seen at the left and more typical diffuse morphology at the right (courtesy Dr. Thomas M. Ulbright).
Figure 4. Juvenile granulosa cell tumor. This tumor from a young boy shows irregular nests with only limited follicular differentiation seen at the left. The paucity of follicles and the immature appearance of the nuclei typical of these cases may cause diagnostic problems and lead to consideration of a yolk sac tumor. Even minimal follicular differentiation may be diagnostically crucial.