Testicular Sertoli cell tumour and potentially testicular Leydig cell tumour are features of <i>DICER1</i> syndrome.

Abstract

<i>DICER1</i> syndrome is a rare paediatric autosomal dominant inherited disorder predisposing to various benign and malignant tumours. It is caused by a germline pathogenic variant in <i>DICER1</i>, and the second hit for tumour development is usually a missense hotspot pathogenic variant in the DICER1 ribonuclease IIIb domain. While <i>DICER1</i> predisposing variants account for about 60% of ovarian Sertoli-Leydig cell tumours, no <i>DICER1</i>-related testicular stromal tumours have been described. Here we report the first two cases of testicular stromal tumours in children carrying a <i>DICER1</i> germline pathogenic variant: a case of Sertoli cell tumour and a case of Leydig cell tumour diagnosed at 2 and 12 years of age, respectively. A somatic <i>DICER1</i> hotspot pathogenic variant was detected in the Sertoli cell tumour. This report extends the spectrum of <i>DICER1</i>-related tumours to include testicular Sertoli cell tumour and potentially testicular Leydig cell tumour. Diagnosis of a testicular Sertoli cell tumour should prompt <i>DICER1</i> genetic testing so that patients with a <i>DICER1</i> germline pathogenic variant can benefit from established surveillance guidelines. <i>DICER1</i> genetic evaluation may be considered for testicular Leydig cell tumour. Our findings suggest that miRNA dysregulation underlies the aetiology of some testicular stromal tumours.