SCSTs vary greatly in prognosis and behavior, depending on the subtype. Therefore, deciding on methods of management for recurrence can be difficult, especially when the tumor is at an unusual site, as in this case. Since disseminated spread is the most common mode of metastasis in ovarian cancer, the gastrointestinal tract is frequently involved. In some advanced cases, determining whether the origin of the tumor is bowel or ovarian can be difficult. The use of immunohistochemical markers such as CK7 and CK20 can assist in the differentiation. The question of tumor origin did not present a problem with this case as the histologic morphology clearly demonstrated a recurrent SCST as opposed to an adenocarcinoma, which could be of ovarian or colonic origin. The majority of gastrointestinal recurrences from ovarian tumors occur via direct transcoelomic spread and invasion of the serosal surface in a centripetal direction. Rose and colleagues [
2] demonstrated metastasis relating to small bowel in 43% of autopsies performed for ovarian cancer. However, it is likely that these tumors have mainly serosal involvement and there were no SCSTs in this series [
2]. Most tumors involving the mucosa of the bowel will show evidence of associated serosal involvement. Reed and colleagues [
3], in a review of 77 autopsy records of ovarian cancer, discovered bowel serosal involvement in 86% and mucosal involvement in 36%. The present case is unusual in that the metastasis appears to have arisen in the mucosa alone, suggesting hematogenous or lymphatic spread. It has been suggested that this spread occurs in epithelial ovarian tumors along bowel wall lymphatic channels, displaying a "buckshot" distribution in which multiple separate foci are seen along a length of bowel mucosa. This lymphatic spread occurs only when there is a high level of intraperitoneal disease, which was not seen in our patient [
4]. Some SCSTs are considered to be of low malignant potential, having a low proliferation rate similar to that of borderline tumors of the ovary. Because these SCSTs are slow-growing, they tend to present at an earlier stage compared with epithelial tumors and have an excellent prognosis; overall five-year survival is 79%. Recurrence and metastasis are rare and often late. More than 50% of recurrences occur after more than five years, and 25% occur after 10 years [
5]. Others such as thecomas and fibromas generally behave in a benign fashion, although features such as mitotic rate, hemorrhage, and necrosis should be regarded with caution as these recurrences may be better regarded as fibrosarcomas. Both luteinized thecomas and stromal Leydig cell tumors are usually regarded as benign, but in our patient, there were worrying features that were identified on the initial histology. Zhang and colleagues [
6] reported a series of 50 ovarian stromal tumors in which luteinized or Leydig cells were present, and four appeared malignant histologically. One patient died early on, one was alive and well at five years, and there was insufficient follow-up on the other two. The authors state that luteinized thecomas and stromal Leydig cells are distinguished only by the presence of crystals of Reinke and that, owing to the difficulty in identifying these structures; some luteinized thecomas may well be unrecognized stromal Leydig cell tumors [
6]. Virilization may encourage to search crystals of Reinke. Very few cases of stromal Leydig cell tumors have been reported. In addition to the series of Zhang and colleagues [
6], two have been reported in young women [
7,
8]. Surgical intervention is generally adopted as the primary mode of treatment; this is often conservative in young women wishing to retain their fertility. Age, large tumor size, lymph node involvement, and residual disease are all predictors of poor prognosis [
5]. Although surgery is likely to remain the foundation for treatment of SCSTs, chemotherapy has been used as an adjunct in particular cases. Various authors have used chemotherapy in selected cases with advanced stage, significant residual disease, metastasis, or recurrence. Although it is likely that chemotherapy provides improved survival in such cases, the optimum regimen is still unclear. As SCSTs are variable in their histologic appearance, many chemotherapy regimens are assessed by using the most common subgroup, the granulosa cell tumor, and the findings are extrapolated to all SCSTs. In addition, owing to the indolent nature of these tumors, long-term follow-up of any proposed treatment is needed to observe the full effects. Hence, optimizing chemotherapy treatment in these cases is a challenge. A number of regimens - including vincristine, doxorubicin, and cyclophosphamide; BEP; and, most recently, taxanes (paclitaxel or docetaxel) - have been used in the past [
9]. A Gynecologic Oncology Group trial used BEP in the treatment of incompletely resected stage II to IV or recurrent SCSTs and found that 69% of primary advanced tumors and 51% of recurrences remained progression-free following treatment, although there were problems of bleomycin-related pulmonary toxicity in a minority of cases [
10]. The use of taxanes with or without platinum has been shown to be as effective as BEP with regard to disease-free survival and overall survival. The taxane group experienced less major toxicity (14% mainly hematologic) compared with the BEP group (24% mainly pulmonary fibrosis or neutropenia). It should be noted that, in all of the studies mentioned above, the majority of tumors were adult granulosa cell tumors and so the findings may not be directly applicable to other SCSTs.