Tumors of the Testis

The clinical term “testicular tumor” is an umbrella term for all intrascrotal masses regardless of their actual anatomic location. In fact, some 90 % of tumors in the scrotum arise in the testis [1], and at least 90 % of them belong to the group of germ cell tumors (GCTs), the incidence of which is continuously increasing in western industrialized countries, especially in central and northern Europe. Although rare, GCTs have been of great interest to the pathologist because of their peculiar biology and morphology and also to the clinician, as they used to be deadly tumors, but nowadays can be cured in more than 90 % of cases. It took a long time before a comprehensive, histogenetically based classification was available, the classification proposed by Mostofi and Sobin in 1977 [2]. The discovery of a precursor lesion [3], originally called “carcinoma in situ of the testis,” supported the theoretical background of this classification.