ABSTRACT
The clinical term ‘testicular tumor’ is a synonym 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). Intrascrotal tumors are classified according to the WHO (2004) classification,2 based on their histologic features and anatomic location. The classification includes 8 major groups (Table 6.1): germ cell tumors, sex cord/gonadal
Germ cell tumors ICD-O Intratubular germ cell neoplasia, unclassified 9064/2 Other types Tumors of one histologic type (pure forms) Seminoma 9061/3
Seminoma with syncytiotrophoblastic cells Spermatocytic seminoma 9063/3
Spermatocytic seminoma with sarcoma Embryonal carcinoma 9070/3 Yolk sac tumor 9071/3 Trophoblastic tumors
Choriocarcinoma 9100/3 Trophoblastic neoplasms other than choriocarcinoma
Monophasic choriocarcinoma Placental site trophoblastic tumor 9104/3
Teratoma 9080/3 Dermoid cyst 9084/0 Monodermal teratoma Teratoma with somatic type malignancies 9084/3
Tumors of more than one histologic type (mixed forms) Mixed embryonal carcinoma and teratoma 9081/3 Mixed teratoma and seminoma 9085/3 Choriocarcinoma and teratoma/embryonal carcinoma 9101/3 Others
Sex cord/gonadal stromal tumors Pure forms Leydig cell tumor 8650/1 Malignant Leydig cell tumor 8650/3 Sertoli cell tumor 8640/1
Sertoli cell tumor lipid rich variant 8641/1 Sclerosing Sertoli cell tumor Large cell calcifying Sertoli cell tumor 8642/1
Malignant Sertoli cell tumor 8640/3 Granulosa cell tumor 8620/1
Adult type granulosa cell tumor 8620/1 Juvenile type granulosa cell tumor 8621/1
Tumors of the thecoma/fibroma group Thecoma 8600/0 Fibroma 8810/0
Sex cord/gonadal stromal tumor incompletely differentiated 8591/1 Sex cord/gonadal stromal tumor, mixed forms 8592/1 Malignant sex cord/gonadal stromal tumor 8590/3 Tumors containing both germ cell and sex cord/gonadal stromal element
Gonadoblastoma 9073/1 Germ cell-sex cord/gonadal stromal tumor, unclassified
(Continued) (Continued)
Miscellaneous tumors of the testis Carcinoid tumor 8240/3 Tumors of ovarian epithelial types
Serous tumor of borderline malignancy 8442/1 Serous carcinoma 8441/3 Well-differentiated endometrioid carcinoma 8380/3 Mucinous cystadenoma 8470/0 Mucinous cystadenocarcinoma 8470/3 Brenner tumor 8960/3
Nephroblastoma 8680/1 Paraganglioma
Hematopoietic tumors
Tumors of collecting ducts and rete Adenoma 8140/1 Carcinoma 8140/3
Tumors of paratesticular structures Adenomatoid tumor 9054/0 Malignant mesothelioma 9050/3 Benign mesothelioma
Well-differentiated papillary mesothelioma 9052/0 Cystic mesothelioma 9055/0
Adenocarcinoma of the epididymis 8140/3 Papillary cystadenoma of the epididymis 8450/0 Melanotic neuroectodermal tumor 9363/0 Desmoplastic small round cell tumor 8806/3
Mesenchymal tumors of the spermatic cord and testicular adnexae
Secondary tumors of the testis (metastases)
1. Tumors of the testis Seminoma: Classical
Spermatocytic Teratoma: Teratoma differentiated (TD)
Malignant teratoma intermediate (MTI) with differentiated or organoid components, but also containing undifferentiated elements Malignant teratoma undifferentiated (MTU) with no mature tissue or organoid structures Malignant teratoma trophoblastic (MTT)
Combined tumor: Seminoma and teratoma in the same testis (CT)
Sertoli cell/mesenchyme tumors (SMT) Interstitial cell tumors (ICT) Yolk-sac tumors Malignant lymphomas Miscellaneous tumors
stromal tumors, miscellaneous tumors of the testis, hematopoietic tumors, tumors of collecting ducts and rete, tumors of paratesticular structures, mesenchymal tumors, and secondary tumors (metastases). The so-called ‘British Classification’ (Table 6.2) proposed by the British Testicular Tumor Panel in the early 1960s1,3 was widely used in Europe until the end of the 1990s. It is slowly disappearing because the new WHO classification has consensually been accepted by pathologists specializing in this field. Furthermore, new cytogenetic and molecular pathologic data strongly support the theoretic background of this classification.
