Novel Somatic Co-occurrence of IDH1 and TENT5C Mutations in Juvenile Granulosa Cell Tumor With Sertoli Elements Occurring in Ollier Disease.

We report a rare ovarian juvenile granulosa cell tumor with Sertoli differentiation occurring in a woman with Ollier disease and concurrent somatic IDH1 R132C and TENT5C mutations. Histology showed a predominantly juvenile granulosa cell tumor with a minor Sertoli-like component, and immunohistochemistry confirmed sex cord-stromal differentiation. The case is notable for the identification of TENT5C, a noncanonical poly(A) polymerase with emerging tumor suppressor relevance. Although not established as a recurrent driver in ovarian sex cord-stromal tumors, TENT5C alterations may represent an additional molecular event contributing to tumor biology alongside IDH1-associated mosaicism.