A family with Sertoli-Leydig cell tumour, multinodular goiter, and DICER1 mutation.

Background: DICER1 syndrome is an autosomal dominant tumour predisposition syndrome associated with a wide variety of cancerous and noncancerous conditions, including ovarian sex cord-stromal tumours and thyroid conditions, including multinodular goiter. The most common ovarian sex cord-stromal tumour associated with DICER1 syndrome is Sertoli-Leydig cell tumour, with germline DICER1 mutations present in more than 50% of cases. We present a case in which a patient in her late 30s was diagnosed with a Sertoli-Leydig cell tumour in the background of a strong family history of multinodular goiter and Sertoli-Leydig cell tumour with a germline mutation in DICER1. Case Presentation: A 38-year-old woman with history of multinodular goiter was found to have stage iiic ovarian Sertoli-Leydig cell cancer after presenting with abdominal pain. She underwent multiple surgeries and chemotherapy. The patient developed rapid disease progression and died 7 months after diagnosis. Seven years earlier, a daughter had experienced the same disease and was found to have a germline DICER1 mutation. The mother had not undergone testing before her own diagnosis. Summary: The co-occurrence of Sertoli-Leydig cell tumour and multinodular goiter is highly suggestive of DICER1 syndrome. The recognition of DICER1 syndrome within a family is essential for increased awareness and potential early recognition of complications. Most conditions associated with DICER1 syndrome occur in childhood, and most of the current screening recommendations are specific for childhood and young adulthood. Cancer risks and findings for the adult population are not as well defined. Clinicians who encounter DICER1 syndrome should review recommendations for genetic testing and surveillance and enrol patients in the DICER1 registry.