Advances in non-germ cell tumours of the testis: focus on new molecular developments in sex cord-stromal tumours.

Testicular sex cord-stromal tumours (TSCSTs) represent ~4%-8% of all testicular neoplasms. Most show a Leydig or Sertoli cell phenotype and exhibit benign clinical behaviour. However, a subset of ~10% is malignant and clinically problematic, as TGCTs do not respond to systemic therapy. Classification of TSCSTs has relied on morphology, with several entities being defined based on their resemblance to more common ovarian counterparts (e.g. granulosa cell tumours). In recent years, multiple clinicopathologic and molecular studies have improved our understanding of the mechanisms that underlie pathogenesis and progression in TSCSTs, providing data that can be useful to refine classification and prognostication. In this review, we summarise the major recent advances in TSCSTs, focusing on molecular alterations and biomarkers relevant for diagnosis, classification and prognosis.