DSRCT is a rare and highly aggressive tumor that commonly affects the abdomen and or pelvis of young males. In their cases series, Al-Ibraheemi et al. reported 16 cases of extra-abdominal DSRCT. These reported sites included the head, neck, intracranial, thigh, axilla/shoulder, inguinal, paratesticular, intraosseous, and uterine body [5]. Moreover, Lae et al. reported DSRCTs originating from the ethmoidal sinus and soft tissue of the scalp [6]. To the best of our knowledge, DSRCT was reported to be originating from the ovary in 18 cases [7]. Interestingly, two of them presented during pregnancy and labor. Most of the reported cases presented with bilateral ovarian involvement with widespread peritoneal nodular infiltration [8, 9].
Its early presentation is usually non-specific, with symptoms varying between vague abdominal pain, distension, and altered bowel habits. Such a tendency to late presentation accounts for its difficult management, as it often manifests in advanced disease stage. Radiologic findings usually describe abdominal masses of variable sizes in association with peritoneal deposits, omental cakes, and ascites, findings that are usually found in the advanced colon, ovarian, and gastric cancer, hence the encountered diagnostic difficulty [10]. Differential diagnosis of small-round-cell tumor includes lymphoma, Ewing sarcoma, medulloblastoma, Wilms’ tumor, synovial sarcoma, neuroblastoma, and embryonal rhabdomyosarcoma [11]. Diagnosis is often confirmed after ultrasonographic- (U\S) or computerized tomography (CT)-guided biopsy from these lesions. Tumor markers’ elevation is non-specific. Only immunohistochemistry (IHC) and cytogenetic study are the tools that can confirm the diagnosis [12, 13]. The typical histopathological appearance of DSRCTs includes large necrotic area, sharply demarcated nests of different sizes containing small round cells with hyperchromatic nuclei and scanty faint eosinophilic cytoplasm, or spindle cells embedded in a desmoplastic stroma. These cells mostly exhibit epithelial, mesenchymal, and neural markers like cytokeratin, desmin, and smooth muscle actin (SMA) [14]. Desmoplastic small-round-cell tumor arises from mesenchymal cells of the abdominopelvic peritoneum. The gene fusion between Ewing sarcoma (EWS) and WT1 genes resulting in the characteristic translocation t(11;22)(p13;q12), is the unique molecular hallmark and no other genetic factor has been linked to this aggressive tumor [15]. Horseshoe kidney is the most common fusion anomaly of the kidneys accounting for 0.25% of the population [16]. One of the major concerns that affected the treatment decision in the present case is the encountered technical difficulty of retroperitoneal lymph node dissection. Also, the radiation oncologist should have a good radiotherapy field planning to avoid radiation nephritis as most of the renal parenchyma overlies the para-aortic lymph nodes. In the abovementioned case, the patient was presented by bilateral ovarian masses, a finding that usually first directs the oncologist’s attention to the possibility of either Krukenberg tumor or primary ovarian cancer [17]. Indeed, this case was handled as such and it was only the final pathology that revealed the diagnosis of this rare tumor. In this case, a complete surgical staging—as if it was a case of primary ovarian cancer—was done given the presenting intraoperative situation and the result of frozen section analysis. Young age in and of itself might raise the suspicion of such malignancy, yet the rarity of the disease should keep us in the lane of common differential diagnoses for such age in an algorithmic fashion. It should be noted that until now there is still no consensus regarding the optimal management of this disease. The treating physician should follow the previously reported multimodality treatment to achieve the best disease response [7]. Based on the available data from the literature, a multimodality therapy of neoadjuvant multiagent chemotherapy followed by cytoreductive surgery and external beam radiotherapy is now considered the standard of care for those patients without extra-abdominal spread [18]. Honoré et al. reported improved overall and progression-free survival in patients treated with multimodality treatment including whole abdominopelvic radiotherapy (WAP RT) of 30 Gy. Fewer side effects were encountered with intensity modulated radiotherapy (IMRT) than two and three dimensional radiotherapy [19]. Despite relapse which was reported in most of the patients during long-term follow-up, prolonged progression-free survival was best reported after multimodality treatment [20]. Prognosis is still dismal with 5-year survival barely exceeding 30%.
