Ovarian stromal tumors containing leydig cells.I. Stromal-leydig cell tumor and non-neoplastic transformation of ovarian stroma to leydig cells

Two examples of a distinctive ovarian tumor composed of nodules of Leydig cells within a neoplastic stromal proliferation are described. The tumors were multinodular and variegated in gross appearance, and one was bilateral. Both women were post-menopausal and were virilized. The tumors arose in a background of ovarian stromal hyperplasia with foci of lutein-like cells. The stromal component of the tumor morphologically resembles theca cell tumor and the presence of numerous crystalloids of Reinke in the lutein-like cells identifies them as Leydig cells. The tumor is considered analogous to a luteinized theca cell tumor, derived from ovarian stroma but with the “male” differentiation. The potential of hyperplastic ovarian stroma to differentiate into Leydig cells in the absence of neoplasia, as shown in two other patients, supports this concept of histogenesis.