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Tumor Discovery Desmoplastic small round cell tumor

that exhibit large and small solid alveoli with high Chemotherapy is often performed using the P6
connectivity, cord-like structures, tubular structures, protocol that combines cyclophosphamide, doxorubicin,
and rosette-like arrangements, which proliferate in an vincristine, ifosfamide, and etoposide. Other drugs
invasive manner and are accompanied by desmoplastic included cisplatin, carboplatin, topotecan, temozolomide,
stroma. Immunohistologically, the tumor was positive for vinorelbine, and irinotecan. High-dose chemotherapy and
11
cytokeratin and was stained with desmin in dots around autologous hematopoietic stem cell transplantation are
the nucleus. 11 sometimes performed, but these have not been shown to
17
These tumors are believed to originate from improve the long-term prognosis. Although DSRCTs are
undifferentiated, multipotent cells. During chemotherapy, chemotherapy-sensitive, they are prone to local recurrence
tumor cells differentiate into rhabdomyoblast-like cells and chemotherapy alone is not effective enough to cure
and express the muscle lineage markers Myo-D and them. This potentially reflects the diversity of tumor cells.
myogenin. 12 Furthermore, rapamycin, an mTOR inhibitor, reduced
EWS-WT1 expression and triggered apoptosis in DSRCT
The molecular biological feature of DSRCTs is the cell lines. However, no clinical benefit has been reported
reciprocal translocation of the EWS-WT1 fusion gene. in patients with DSRCTs treated with rapamycin alone.
18
EWS is located on chromosome 22q12 and encodes a In addition, the tumor progression was reported to be
member of the TET family of RNA-binding proteins. suppressed for 56 weeks when sunitinib, a multikinase
Furthermore, the TET family proteins are thought to be inhibitor that targets VEGFR1, 2, 3, PDGFR-α, PDGFR-β,
involved in transcription and splicing. The EWS gene KIT, FLT-3, RET, and CSF-1, was administered. In this
1,19
is also related to other sarcomas, such as EWS-FLI1 and instance, due to the delay between surgery and pathological
EWS-ERG fusion genes in Ewing’s sarcoma. Furthermore, diagnosis, we initiated adjuvant chemotherapy with
WT1 is located on 11p13, and the WT1 protein contains paclitaxel, carboplatin, and bevacizumab with no evidence
a zinc finger DNA-binding region that is responsible for of recurrence during treatment, suggesting potential
the transcription and post-transcriptional regulation of efficacy. After recurrence, lenvatinib plus pembrolizumab
many target genes. The reciprocal translocation t (22:11) was administered because lenvatinib has effects comparable
(q12: p13) fuses the N-terminal region of WS with the to those of sunitinib; however, the patient showed no
C-terminal DNA-binding region of WT1. The resulting response. In addition, the effects of immune checkpoint
chimeric protein acts as an abnormal transcription factor inhibitors are uncertain.
that causes desmoplastic small-cell tumors. In addition,
the EWS-WT1 fusion protein is thought to regulate the A report summarizing the treatment results of 66 cases of
expression of various genes involved in carcinogenesis, such DSRCTs from the Memorial Sloan Kettering Cancer Center
as IGF-1 receptor, PDGFα, PAX2-2, WT-1, ENT4, TALLA- found that while there were no survivors in cases without
1, and IL2/15Rβ. 13-16 Although atypical, this mechanism surgery, the 3-year survival rate of patients who underwent
20
may also be involved in the development of Wilms tumor, tumor resection was 58%. However, in this case, distant
hypercalcemic small cell carcinoma of the ovary, gonadal metastasis occurred relatively early, despite a complete
cell tumor, and undifferentiated small round cell tumor, in surgical procedure, and although it appeared to be localized
addition to DSRCT. within the peritoneal cavity, micro-distant metastasis may
have already occurred. Thus, the present case appears to
Primary treatments include surgery, radiation highlight a case-specific discrepancy regarding the effect of
therapy, chemotherapy, and molecular-targeted drugs. complete surgical resection on prognosis. Furthermore, if
However, no standard treatment exists. Techniques, such possible, a more precise diagnosis using PET is desirable
as radiofrequency ablation, gamma knife, cryoablation, when formulating a treatment strategy. However, prediction
and vascular embolization, are used to treat metastatic of this disease is impossible, and may not be realistic.
lesions. Surgical therapy, often entailing omentectomy,
splenectomy, or lymph node dissection, is commonly 4. Conclusion
performed. Achieving negative margins is typically
impractical because of the tumor invasiveness. In this case, Herein, we report a case of primary desmoplastic small
although the lymph node and liver metastases recurred, round cell ovarian tumor. We hope that, by accumulating
there was no intraperitoneal recurrence, such as peritoneal such cases, standard treatment can be established.
dissemination or ascites. Despite slight rectal adhesions, Acknowledgments
no visible residual disease or local pelvic recurrence was
detected during surgery, suggesting completeness of the We would like to thank Editage (www.editage.com) for the
procedure. English language editing.

Volume 4 Issue 2 (2025) 109 doi: 10.36922/td.7104