The 2022 World Health Organization classification of germ cell tumors and updates of American Joint Committee for Cancer tumor staging classification

• Published in: Diagnostic histopathology (Oxford, England : 2008) England : 2008), 2023-06, Vol.29 (6), p.259-268
• Main Authors: Kilic, Irem, Idrees, Muhammad T.
• Format: Article
• Language: English
• Subjects: Embryonic-type neuroectodermal tumor; germ cell tumor; teratoma; testicular cancer; testis staging; WHO classification
• ISSN: 1756-2317; 1876-7621
• DOI: 10.1016/j.mpdhp.2023.03.001

Testicular tumors are most common in young men between 15 and 45 years of age. Germ cell tumors make up the biggest proportion of malignant tumors of the testis. Due to the diverse morphologic spectrum and overlapping morphologies, it is a very challenging area in the anatomic pathology field, which needs significant expertise and experience to render a precise diagnosis. The World Health Organization (WHO) has recently presented a new tumor classification with significant modifications in nomenclature as well as some refinement of criteria. The changes encompass germ cell tumors, sex cord stromal tumors, and tumors arising from testicular appendages. The "primitive neuroectodermal tumor (PNET)" terminology is replaced with "embryonic-type neuroectodermal tumor (ENET). The carcinoid terminology is replaced with neuroendocrine tumors (NET). In sex cord stromal tumors, two new entities were included, "Signet ring stromal tumor" and "Myoid gonadal stromal tumor" in the new classification. Sertoliform cystadenoma is now considered a sertoli cell tumor (NOS). "Well-differentiated papillary mesothelioma" is now termed as "well-differentiated papillary mesothelial tumor." Tumor Node Metastasis (TNM) Classification published by the American Joint Committee for Cancer (AJCC) is recommended for testicular tumors listed as germ cell tumors. In its 8th edition, the AJCC has provided regular updates in printed form as AJCC tumor classification. Currently, the AJCC has changed its process of publishing the TNM classification and is moving away from editions, and the new updates will be released as versions. Several organ systems have already updated the content, while the remaining will be updated per their scheduled timeline.