Virilizing ovarian tumors account for less than 5% of all ovarian neoplasms [6]. Sex cord-stromal tumors, are derived from the sex cord and stromal components of the developing gonad [4]. Steroid cell tumors are a subtype of ovarian sex cord-stromal tumors that are composed entirely of steroid-secreting cells and account for 0.1% of all ovarian neoplasms [2]. Steroid cell tumors are usually virilizing, frequently secreting testosterone; however, they may be endocrinologically inert or estrogenic. As many as one-quarter of steroid tumors exhibit malignant behavior [4].
Steroid cell tumors are further subclassified into stromal luteoma, Leydig cell tumors (hilar and nonhilar), and steroid cell tumors that are not otherwise specific [7]. Most pure Leydig cell tumors of the ovary arise from the hilus cells, or hilar-Leydig cells, which have the morphologic features of testicular Leydig cells and can be found in the ovarian hilus in more than 80% of adult women. These tumors are classified under the category of steroid cell tumors (lipid cell tumors) because they may be difficult or impossible to differentiate histologically from ovarian tumors of other steroid cell types [4].
The clinical manifestations are to a large extent determined by the age of presentation, hormonal activity, and virilizing properties of the tumor. Virilization or hirsutism is encountered with three fourths of Leydig cell tumors [7].
The clinical presentation may take many forms, including abdominal pain, abdominal distention, and bloating. However, the more noticeable presentations are those associated with the hormonal activity and virilizing properties of the tumor [8]. Signs and symptoms of masculinizing tumors usually take place in two definite phases, an early phase of defeminization and a subsequent phase of masculinization. Typically, a menstruating female will first notice oligomenorrhea or amenorrhea. There is regression of the breasts and external genitalia, atrophy of the uterus and adnexa, and loss of the female body contour. This is followed by hirsutism, acne, clitoral enlargement, increased libido, sterility, enlargement of the larynx, deepening of the voice, and temporal alopecia [9, 10]. On the other hand, these tumors may produce little or no androgenic activity and could, in fact, show some evidence of estrogenic effect [4, 10].
With regard to blood investigations, detecting the source of the androgenic tumor is a process of exclusion. In our patient, the high serum free and total testosterone confirmed the presence of a virilizing neoplasm. A dexamethasone suppression test failed to alter basal values, moreover, 17-hydroxyprogesterone levels were also within normal limits; this ruled out a potential adrenal source of the androgens [11, 12].
On radiological imaging, appearances of virilizing tumors of the ovary depend, to some extent, on the tumor type. Virilizing steroid cell tumors of the ovary are usually one sided and often very small, measuring only slightly bigger than the normal ovary [9, 10]. They are usually confined to the ovary at presentation, predominantly solid or mostly solid, non-calcified, and not associated with ascites. Small steroid cell tumors have been described as slightly hypoechoic or hyperechoic (compared to the ovary) with high diastolic flow on Doppler interrogation. They may be difficult to identify on radiological imaging, in part because they are isoechoic to the uterus on ultrasound and isoattenuating on CT [13, 14]. Techniques such as MRI with phased array coils, or color Doppler imaging, can possibly detect smaller tumors than more conventional imaging methods [13–15]. In our patient, abdominal ultrasound examination was unremarkable except for the presence of ovarian cysts. A CT-scan and an MRI helped in confirming the existence of a mass lesion involving the left adnexa. It was the post-operative histopathological study, however, that helped in clinching the final diagnosis as the presence of Reinke's crystalloid is diagnostic for Leydig cell tumors [4, 5, 9].
Though steroid cell tumors of Leydig-cell subtype are usually benign, there is still a potential risk for malignant transformation [5, 9, 10]. Surgery remains the mainstay in the management of these neoplasms as, in addition to overcoming the above risk, however small, the removal of the tumor is usually followed by near-complete regression of the presenting symptoms. Initially, the signs of defeminization, such as flattened breasts and loss of fat around the hips, are reversed. Subsequent to this, the virilizing effects disappear slowly; the hypertrophied clitoris and the deepening of the voice, however, frequently persist [6, 10].