[Histopathological analysis of germ cell tumours: aspects to consider].

Germ cell tumours (GCT) are the most common testicular tumours and form a heterogenous group of tumours with different biological behaviour. Based on differences regarding patient age at first manifestation, morphological characteristics and molecular changes, they are divided into three different groups of GCTs (type I-III). For treatment and prognosis, an exact histopathological analysis of an orchiectomy resection specimen is very important, including the specification of all different histological subtypes with their proportional distribution. This article describes the approach of the preparation of a resection specimen and the histopathological analysis of a testicular tumour. In addition, it describes cases in which additional tools like immunohistochemical and molecular analyses are necessary. Furthermore, the current WHO classification of testicular GCT is discussed.