FINAL DIAGNOSIS OVARIAN STEROID CELL TUMOR, NOT OTHERWISE SPECIFIED (NOS).
All other parts of the case showed no evidence of neoplasm, including the right and left IP Ligaments and fallopian tubes, omentum, appendix, lymph nodes and abdominal peritoneal biopsies. The companion pelvic cytology specimen was also negative for malignant cells.
Steroid cell tumors, NOS, comprise <0.1% of all ovarian tumors. The mean age for these tumors is around 40 (ranging from 2.5 to 80 years). These tumors are usually associated with androgenic manifestations, as they were in this case, and are less often associated with estrogenic and rarely with cushingoid changes, progestogenic effects or paraneoplastic syndromes. These tumors have been found to be bilateral in a minority of cases.
Grossly, these tumors have been known to range from 1.2 up to 45 cm in greatest dimension, although they are often large. Most of these tumors are well-circumscribed, lobulated and multinodular. The neoplastic tissue is mostly solid with some cystic changes. The color ranges from brown to yellow to gray-white with occasional foci of hemorrhage and necrosis noted especially in large tumors. The more lipid or lipochrome pigment, the more yellow the tumor.
Microscopically, these tumors usually consist of diffusely arranged cells, but nests, clusters, cords, and columns are also seen. The scant or sparse stroma may consist of delicate connective tissue supporting a rich vascular network. The stroma may also be fibromatous, hyalinized, edematous or myxoid. Tumor cells are generally of two types. The first type is polygonal, medium to large and contain eosinophilic, slightly granular cytoplasm with a single, small, uniform nucleus with a central nucleolus. The second cell type is larger with abundant, clear vacuolated cytoplasm with distinct cell membranes and small, dark nuclei. The cells lack Reinke crystals. Various grades of nuclear atypia and numbers of mitoses have been seen in these tumors.
These tumors are usually immunoreactive to alpha-inhibin and variably with anti-cytokeratin antibodies and vimentin.
Hayes et al. in 1987 looked at these tumors in terms of their malignant potential. The authors arbitrarily defined "probably benign" tumors as those tumors with no evidence of spread beyond the ovary within three or more years postoperatively. Tumors that showed spread beyond the ovary during this time period were considered clinically malignant; in this particular study 18 out of 50 patients (43%) were found to have a clinically malignant tumor. The authors found that the best pathological correlates of malignant behavior were the presence of ?2 mitoses/10 high power fields (92% malignant), a diameter of ?7 cm (78% malignant), a nuclear grade 2 or 3 atypia (64% malignant), hemorrhage (77% malignant) and necrosis (86% malignant). However, tumors without these histologic features have occasionally been found to behave in a malignant fashion.
The differential for an ovarian steroid cell tumor (and differentiating them from ovarian steroid cell tumors, NOS) includes:
Our tumor was large (9cm) and extended to the surface of the ovary. It was not limited to the ovarian stroma and had no Reinke crystals. The tumor was positive for inhibin, negative for EMA and showed patchy reactivity for Melan-A. In addition, the lesion demonstrated 3-4 mitoses/10HPF, a nuclear grade 2 and vascular space invasion, which in addition to the overall diameter of the tumor suggests an aggressive behavior for this particular lesion. This ovarian steroid cell tumor, NOS, although having low pathologic (pT1cN0MX) and clinical stage (IC), may have some malignant potential for which close clinical observation is required.
Contributed by Marian Rollins-Raval, MD MPH and Rohit Bhargava, MBBS