Intro-abdominal Desmoplastic Small Round Cell Tumor: A Description Of One Case And Review Of The Literature

Background and Objective: Desmoplastic small round cell tumor (DSRCT) is a recently described rare and highly aggressive malignancy, typically occurring in adolescent and young males. The tumor usually presents in abdominal-pelvic cavity with metastases common to peritoneum, liver and lymphoid tissues. Bulky peritoneal soft-tissue masses without an apparent organ-based primary site is the imaging characteristic of intra-abdominal desmoplastic small round cell tumor(IDSRCT). Histologically, it has a nesting pattern of cellular growth within dense desmoplastic stroma. The immunohistochemical profile shows divergent differentiation, co-expressing epithelial, mesenchymal, neural and myogenic markers. Cytogenetical studies have demonstrated a specific chromosome abnormality, t (11;22) (p13;q12), expressing distinct EWS-WT1 protein. No standard treatment protocol has been established and its outcome remains dark with a mean survival period about 1.5-2.5 years in spite of therapeutic progress. The multidisciplinary treatments including high-dose chemotherapy, aggressive debulking surgery, radiation and myeloablative chemotherapy with stem cell rescue are the main therapy recently. The combined chemotherapy is always alkylate-based, including cyclophosphamide, iphosphamide, cisplatin, etoposide, vinblastine, adriamycin and 5-fluorouracil. Theobjective of this work is to report a personal observation of one IDSRCT and review the literatures to clarify the epidemiological, clinical, pathological and therapeutic aspects of this rare tumor.Patient and Methods: A 35-year-old male with palpable abdominal masses and distention was admitted into our hospital who was accurately diagnosed as IDSRCT by biopsy of the mass. He was treated with 6 cycles of first-line chemotherapy including cyclophosphamide, vincristine and epirubicin, then underwent aggressive surgery which was followed by a second chemotherapy with isofosfamide and etoposide. At the same time, the epidemiological, clinical, radiologic, pathohistological and immunohistochemical features are examined and analyzed.Results: The patient had the typical epidemiological, clinical, radiologic, pathohistological and immunohistochemical features of IDSRCT with elevated serum CA125 and hCG which are not common. He had obtained a partial response after the first-line chemotherapy, presenting as tumor diminution and disappearance of hepatic metastases, decrease of CA125 and hCG as well. The 3 cycles of additional postoperation chemotherapy also resulted in tumor shrinkage, though it was stopped because of severe heptic functional lesion. Unfortunately, the tumor relapsed with reincreased CA125 and intestinal obstruction after maintaining the disease in a stable state for several months, resulting in a second-look laparotomy and palliative resection. The patient was subsequently started on another further chemotherapy containing irinotecan and cisplatin, which had attained a partial response again. Until now the patient has finished 7 cycles of the further chemotherapy and been alive with the neoplasm for 26 months after being diagnosed.Conclusions: The diagnosis of DSRCT can be considered in adolescents and young adults with typical imaging findings of bulky peritoneal soft-tissue masses, without an apparent organ-based primary site, which however can be established with correlation of clinical, pathohistological, immunohistochemical and cytogenetic features. This experience confirms that DSRCT is a rare and highly lethal diseasesince the majority of patients are unresectable when diagnosed and some patients with chemosensitive tumours usually result in short-lasting response to chemotherapy and high rate of recurrence. Anyway, the recent literatures suggest that multidisciplinary treatments including radical surgical excision, multi-agent chemotherapy and radiotherapy or additional blood stem cell transplantation might be the proper approaches to this rare malignancy.