Assessment and classification of sex cord-stromal tumours of the testis: recommendations from the testicular sex cord-stromal tumour (TESST) group, an Expert Panel of the Genitourinary Pathology Society (GUPS) and International Society of Urological Pathology (ISUP)

Abstract

Aims: Testicular sex cord-stromal tumours (TSCSTs) are relatively rare, accounting for ~5% of all testicular neoplasms. They were historically classified into Leydig cell tumour, Sertoli cell tumour, granulosa cell tumour, and unclassified sex cord-stromal tumour. More recently, classification was expanded to incorporate additional histologic types, including some associated with inherited cancer predisposition syndromes. However, the classification of TSCSTs still relies entirely on morphology, with some tumour types being defined based on their resemblance to ovarian counterparts. In recent years, molecular studies have identified drivers and genomic alterations associated with aggressive behaviour and progression; however, these findings have not yet impacted classification and management.

Methods and results: Under sponsorship of the International Society of Urological Pathology (ISUP) and the Genitourinary Pathology Society (GUPS), a group of genitourinary pathologists was assembled in 2023 with the aim of assessing how to use these new data to improve the classification and management of TSCSTs.

Conclusions: This paper summarizes the recommendations derived from the consensus activities and the first meeting of the testicular sex cord-stromal tumour (TESST) group (held at Johns Hopkins Hospital, Baltimore, USA, 3/23/2024).

Keywords: Leydig cell tumour; Sertoli cell tumour; granulosa cell tumour; myoid gonadal stromal tumour; sex cord‐stromal tumour; testis.

Figure 1

Testicular sex cord‐stromal tumour without overt tubular or corded architecture (A). This tumour shows nuclear beta‐catenin expression (B). Recent data suggest that these neoplasms may represent morphologic outliers of Sertoli cell tumour not otherwise specified.

Figure 2

Areas with subtle spindle cell morphology (A) and univacuolated (‘signet ring’‐like) cells (B) in otherwise typical Sertoli cell tumour not otherwise specified.

Figure 3

Inflammatory and nested testicular sex cord tumour with prominent inflammatory infiltrates appreciated at low magnification (A). Micrographs at higher magnification highlight nests of epithelioid neoplastic cells with eosinophilic to clear vacuolated cytoplasm (B, C).

Figure 4

Juvenile granulosa cell tumour of the testis. This tumour shows striking morphologic resemblance to ovarian counterparts, with microfollicles containing thin basophilic mucinous secretion, separated by prominent fibrous septae (A). Tumour cells are small, with an ovoid to stellate shape, and have small irregular nuclei, often lacking noticeable nucleoli (B).

Figure 5

Fumarate hydratase (FH)‐deficient Leydig cell tumour (A). Immunohistochemistry demonstrates loss of FH expression in tumour cells, with retained expression in infiltrating inflammatory cells (B). Of note, the primary tumour did not show aggressive histopathologic features and nonetheless metastasized many years after the original diagnosis (the images correspond to the metastasis). Case courtesy of Dr. Maurizio Colecchia.