Ossifying well-differentiated Sertoli-Leydig cell tumor of the ovary

A unique case of an ovarian sex cord-stromal tumor occurring in a pregnant 20-year-old is described. The tumor showed central ossification on macroscopic examination. Microscopically, cords and nests of Sertoli cells were identified, mostly away from the abundant central hyalinization, calcification, and ossification. A small number of Leydig cells were present, with isolated Reinke crystals. The presence of these cells could reflect luteinized stromal cells secondary to pregnancy. The Sertoli cells were dominant and the calcified/ossified areas were at the center of a dominant Sertoli nodule. This degree of ossification has never been reported in either ovarian Sertoli tumors or well-differentiated Sertoli-Leydig tumors. Calcifying Sertoli cells neoplasms have been described in the testis, but this case appears to be the first description of a case with similar features in the ovary.