Histopathologic and immunohistochemical study of steroidogenic cells in the stroma of ovarian tumors

The presence of steroidogenic or enzymatically active stromal cells in ovarian tumors can lead to various endocrine manifestations by the overproduction of sex steroids. We studied the clinicopathologic and immunohistochemical features of histologically identified steroid-type cells or enzymatically active cells in the stroma of ovarian lesions. Among 1,249 ovarian tumors or tumorlike lesions, steroid cells were histologically identified in the stroma in 32 ovarian neoplasms, of which 29 were mucinous cystadenomas. The cells were Leydig- or hilus-type cells in 4 of the tumors and were lutein-type cells in the remaining 28. None of the 32 tumors were immunoreactive for human chorionic gonadotropin or luteinizing hormone. Lutein-like steroid cells were intermingled with spindle-shaped stromal cells and capillaries, while Leydig-type cells were more often associated with dilated vessels. The transcription factor of steroidogenesis, adrenal 4- binding protein (Ad4BP), was present in nearly all steroid-type stromal cells. However, steroidogenic enzymes, 17α-hydroxylase (C17) and 3β- hydroxysteroid dehydrogenase (3βHSD), were expressed only in 10 of 15 cases of histologically identified steroid cells. Steroid cells in which Ad4BP but not C17 or 3βHSD were expressed were all lutein-type. Aromatase was rarely detected in lutein-and Leydig-type cells. The presence of morphologically identified steroid cells does not necessarily indicate expression within these cells of steroidogenic enzymes, a finding that merits further attention.