Morphological change of the tumor. A, The remaining normal rete testis tissue was present in the peripheral area of the tumor. B, The area comprising irregular tubules with highly collagenized stroma represented adenomatous hyperplasia of the rete testis. C, In the distended tubules, the cells formed apparent papillary patterns. D, The apparent necrosis (black arrow) was present in the papillary structure. E, The area was composed of irregular small tubules and complicated papillary structures with little collagenized stroma. F, The cells had marked cellular atypia with dark staining chromatin and conspicuous nucleoli.