Testicular Cancer - Classification

Classification

Although testicular cancer can be derived from any cell type found in the testicles, more than 95% of testicular cancers are germ cell tumors. Most of the remaining 5% are sex cord-gonadal stromal tumours derived from Leydig cells or Sertoli cells. Correct diagnosis is necessary to ensure the most effective and appropriate treatment. To some extent, this can be done via blood tests for tumor markers, but definitive diagnosis requires examination of the histology of a specimen by a pathologist.

Most pathologists use the World Health Organization Classification system for testicular tumours:

• Germ cell tumours
  • Precursor lesions
    • Intratubular germ cell neoplasia
      • Unclassified type (carcinoma in situ)
      • Specifed types
  • Tumours of one histologic type (pure forms)
    • Seminoma
      • Variant - Seminoma with syncytiotrophoblastic cells
    • Spermatocytic seminoma
      • Variant - spermatocytic seminoma with sarcoma
    • Embryonal carcinoma
    • Yolk sac tumour
    • Trophoblastic tumours
      • Choriocarcinoma
        • Variant - monophasic choriocarcinoma
      • Placental site trophoblastic tumour
      • Cystic trophoblastic tumour
    • Teratoma
      • Variant - Dermoid cyst
      • Variant - Epidermoid cyst
      • Variant - Monodermal teratoma (Carcinoid, Primitive neuroectodermal tumour (PNET), Nephroblastoma-like tumor, others.
      • Variant - Teratomic with somatic-type malignancy
  • Tumours of more than one histologic type (mixed forms)
    • Embryonal carcinoma and teratoma
    • Teratoma and seminoma
    • Choriocarcinoma and teratoma.embryonal carcinoma
    • Others
• Sex cord/Gonadal stromal tumours
  • Leydig cell tumour
  • Sertoli cell tumour
    • Lipid rich variant
    • Scleriosing variant
    • Large cell calcifying variant
    • Intratubular sertoli cell neoplasia in Peutz-Jeghers syndrome
  • Granulosa cell tumour
    • Adult type
    • Juvenile type
  • Thecoma Fibroma Group
    • Thecoma
    • Fibroma
  • Sex cord/gonadal stromal tunour - incompletely differentiated
  • Sex cord/gonadal stromal tumour - mixed types
• Mixed Germ Cell and Sex Cord/Gonadal Stromal Tumours
  • Gonadoblastoma
  • Germ cell-sex cord/gonadal stromal tumour, unclassified
• Miscellaneous tumours of the testis
  • Carcinoid
  • Tumours of ovarian epithelial types
    • Serous tumour of borderline malignancy
    • Serous carcinoma
    • Well differentiated endometrioid tumour
    • Mucinous cystadenoma
    • Mucinous cystadenocarcinoma
    • Brenner tumour
  • Nephroblastoma
  • Paraganglioma
• Haematopoietic tumours
• Tumours of collecting ducts and rete
  • Adenoma
  • Carcinoma
• Tumours of the paratesticular structures
  • Adenomatoid tumour
  • Malignant and Benign Mesothelioma
  • Adenocarcinoma of the epididymis
  • Papillary cystadenoma of the epididymis
  • Melanotic neuroectodermal tumour
  • Desmoplastic small round cell tumour
• Mesenchymal tumours of the spermatic cord and testicular adnexae
  • Lipoma
  • Liposarcoma
  • Rhabdomyosarcoma
  • Aggressive angiomyxoma
  • Angiomyofibroblastoma-like tumour (see Myxoma)
  • Fibromatosis
  • Fibroma
  • Solitary fibrous tumour
  • Others
• Secondary tumours of the testis