Intra-abdominal desmoplastic small round cell tumor in children: a clinicopathologic study

Treatment of Desmoplastic Small round Cell Tumor with Image-Guided Intensity Modulated Radiation Therapy as a Component of Multimodality Treatment

Aims and background

The authors report the case of a 31-year-old black male diagnosed with a pelvic desmoplastic small round-cell tumor who was treated with a unique radiotherapy approach incorporating intensity-modulated radiotherapy and daily ultrasound localization to ensure accurate tumor targeting. Desmoplastic small round-cell tumor is a very rare tumor, most commonly presenting in the abdominopelvic regions of adolescents and young adults. It has generally been associated with a very poor prognosis.

Methods

The patient initially underwent biopsy of the mass and omentectomy for mesenteric implants followed by chemotherapy. Chemotherapy resulted in tumor shrinkage and was followed by a second-look laparotomy. Additional omental nodules were resected, but the primary tumor was adherent to the rectum and seminal vesicles. A radiation oncology consult was obtained, and a course of image-guided intensity-modulated radiotherapy ensued with daily ultrasound localization. This resulted in shrinkage of local disease, but a new lesion was identified. The patient was subsequently started on further chemotherapy, which has maintained the disease in a stable state for several months.

Conclusions

Image-guided intensity-modulated radiotherapy is a feasible option in the treatment of pelvic desmoplastic small round-cell tumor. Such therapy may permit escalation of conventional radiotherapy doses and could have a favorable impact on local control of disease. Confirmation of this belief will require additional data in the form of case reports like this. Pending such confirmation, we continue to be of the impression that desmoplastic small round-cell tumor has an overall unfavorable prognosis, regardless of treatment modalities employed.

Intraabdominal desmoplastic small round cell tumour

Desmoplastic small round cell tumour (DSRCT) is an extremely rare neoplasm. Adolescent males and young adults are most frequently affected. It is highly malignant, with only 29% of patients surviving up to 3 years. This paper documents two cases, one of which, at 4 years old, is the second youngest case documented. Case 1, a 10-year old boy, presented with a 20-day history of choluria, acholia, asthenia, anorexia, and right abdominal pain. Laboratory values were altered, and imaging showed multiples masses in the liver and retroperitoneum. A minilaparotomy was carried out, and a biopsy showed a stage III DSRCT. He was treated with chemotherapy but died of hepatic failure. Case 2, a 4-year-old boy, presented with a 2-month history of abdominal distension. Several hard masses were palpated in the abdomen, and a right inguinal mass that compressed the right testis was observed. Biopsy of the inguinal tumour showed a DSRCT. After treatment with chemotherapy, two operations were carried out to resect different intraabdominal masses. The patient died with peritoneal carcinomatosis 2 months after the last operation. The first patient died due to the advanced stage of the disease, and the second died after chemotherapy, peripheral blood stem transplantation, and multiple operations. The occurrence of this type of tumour in the paediatric age group as well as its high malignancy is noteworthy. Until more effective forms of treatment are found, we recommend treatment with chemotherapy, surgery, and radiotherapy, with close monitoring of the patient.

Desmoplastic small round cell tumor: a clinicopathologic, immunohistochemical, and molecular study of 32 tumors

Desmoplastic small round cell tumor is a rare, aggressive neoplasm that mainly affects young male patients and is characterized by a reciprocal translocation t(11;22)(p13;q12) associated with the EWS-WT1 gene fusion transcript. Clinical, histopathologic, immunohistochemical, and molecular genetics features were reviewed for 32 tumors. There were 29 male and three female patients, with ages from 6 to 54 years (mean, 25 years). The main clinical signs and symptoms included abdominal pain (eight patients), weight loss (five patients), and presence of umbilical hernia (four patients). Two tumors primarily involved the ethmoid sinus and the soft tissues of the scalp; the other tumors (mean size, 10 cm) involved the abdominal cavity (88%). One patient presented initially with an axillary lymph node metastasis. Generally, all tumors showed the typical histologic findings of variably sized clusters of small, round, or spindled cells lying in a desmoplastic stroma. The neoplastic cells in formalin-fixed, paraffin-embedded tissue sections were positive for desmin (dot pattern) (81% of the cases), WT1 (91%), keratin (87%), neuron-specific enolase (84%), CD99 (23%), and actin (3%). The EWS-WT1 gene fusion transcript was detected in 29 of 30 tumors. One tumor with typical clinicopathologic and immunohistochemical features did not show the gene fusion. Follow-up for 27 patients showed that 19 patients (70%) died of uncontrolled, local, or widespread metastatic disease 3-46 months (mean, 20 months) after diagnosis, and eight patients were alive with known evidence of disease. Occasionally, desmoplastic small round cell tumor lacks the classic clinical, histologic, and immunohistochemical features. This study emphasizes the utility of analysis of the EWS-WT1 gene fusion transcript, which was performed on paraffin-embedded tissues, to confirm the diagnosis.

Successful dose-intensive treatment of desmoplastic small round cell tumor in three children

Desmoplastic small round cell tumor (DSRCT) is a rare soft tissue tumor of primitive origin occurring primarily in children and young adults. Based on published reports in the literature, the response to conventional chemotherapy is poor. We report three pediatric patients successfully treated with dose-intensive, multimodal therapy. Between August 1994 and March 1998, we evaluated three consecutive patients with DSRCT at Children's Hospital and Regional Medical Center, Seattle, Washington. We established the diagnosis based on clinical presentation, radiologic staging, and pathologic review with immunohistochemical staining. All patients received a combined modality protocol including dose-intensive chemotherapy (two of them with peripheral blood stem cell [PBSC] support), second look surgery, and consolidative local irradiation. The patients remain in continuous remission at 66, 42, and 26 months after diagnosis, respectively. Two of our patients were younger than any previously reported patient, extending the age group for which DSRCT should be considered on diagnosis of small round cell tumors. The uniform survival achieved in our series indicates potential benefit for the combination of dose-intensive multiagent chemotherapy, local irradiation, and aggressive surgical approach in this disease.

Desmoplastic small round cell tumor: II: an ultrastructural and immunohistochemical study with emphasis on new immunohistochemical markers

In order to investigate the histogenesis and facilitate the diagnosis of desmoplastic small round cell tumor (DSRCT), 39 cases were studied by immunohistochemical methods using a large battery of antibodies directed against a wide variety of epithelial, mesenchymal, and neural-associated proteins. Sixteen of these tumors were also studied by electron microscopy. Thirty-seven of 39 cases reacted for cytokeratin using a "cocktail" of 3 monoclonal antibodies (CAM 5.2/AE1/AE3), 39/39 for desmin, 24/25 for epithelial membrane antigen, 22/27 for vimentin, 18/25 for neuron-specific enolase, 10/15 for CD57 (Leu-7), 3/19 for synaptophysin, 1/22 for chromogranin, 3/19 for muscle-specific actin, 3/16 for alpha-smooth-muscle actin, 11/16 for CD15 (Leu-M1), 5/12 for CA-125, 6/17 for CD99, 9/10 for MOC-31, 2/6 for NB84, 5/7 for Ber-EP4, and 8/9 for the Wilms tumor (WT1) protein. No staining was obtained in any of the cases tested for cytokeratin 5/6 or 20, neurofilament proteins, glial fibrillary acidic protein, peripherin, CA19-9, thrombomodulin, alphafetoprotein, carcinoembryonic antigen, TAG-72 (B72.3), placental alkaline phosphatase, S-100 protein, HMB-45, myoglobin, or for the two myogenic regulatory proteins myogenin and MyoD1. A frequent ultrastructural finding was the presence of juxtanuclear aggregates of intermediate filaments, but microfilaments with densities or Z-band-like material suggestive of either smooth or skeletal muscle differentiation were not seen in any case. Dendritic-like processes containing microtubules and dense core granules were seen in four tumors and all of these tumors reacted for at least one of the neural markers investigated. Although ultrastructural and immunohistochemical studies confirmed previous observations that DSRCTs present epithelial, mesenchymal, and neural phenotypes, a great variation was found in the frequency of expression of the different markers used to demonstrate each line of cell differentiation. The absence of expression of cytokeratin 5/6 and thrombomodulin together with positive staining for CD15, MOC-31, and Ber-EP4 argues against the possible mesothelial origin that has been suggested for this tumor. Additionally since none of the tumors reacted for myogenin or MyoD1, desmin expression in DSRCT cannot be regarded as evidence of skeletal muscle differentiation. Although the histogenesis of DSRCT remains unknown, it is believed that this tumor originates from a progenitor cell with potential for multiphenotypic differentiation.

Desmoplastic small round cell tumor: I: a histopathologic study of 39 cases with emphasis on unusual histological patterns

The clinical and histological features of 39 cases of desmoplastic small round cell tumor (DSRCT) diagnosed at M.D. Anderson Cancer Center are presented. Thirty-two of the patients were men and seven were women ranging in age from 10 to 41 years (mean, 25 years). Twenty-five of the 35 patients for whom follow-up information was available died of widespread metastases 8 to 50 months (mean, 25.2 months) from the time of their diagnosis and the remaining 10 were alive with disease. With the exception of two cases that occurred in the liver and in the scrotum, respectively, all of the cases originated within the abdominal and/or pelvic peritoneum. Eight tumors also involved the retroperitoneum. Although the characteristic histologic pattern of "small, blue cells" embedded in a dense fibrous stroma was seen in most cases, about one third of the tumors exhibited a wide range of morphologic features. The recognition of these uncommon morphologic variants of DSRCT is of paramount importance to avoid a misdiagnosis because these tumors could potentially be confused with other neoplastic conditions.

Desmoplastic small round cell tumors: prognostic indicators and results of surgical management

BACKGROUND

Desmoplastic small round cell tumors (DSRCT or DSCT) are rare aggressive cancers of adolescence and early adulthood. There are few reported series to guide clinical therapy. This study correlates survival with treatment variables, including aggressive surgical debulking.

METHODS

Thirty-two patients with documented DSRCT received treatment at our institution. Demographic, clinical, and treatment variables were correlated with progression-free survival using log-rank statistics.

RESULTS

Thirty patients were male (96%), and two were female (4%), with a median age at diagnosis of 22 years. The primary site of disease in 97% of cases was the abdomen or pelvis. Twenty-nine patients (91%) had extensive disease involving peritoneal surfaces, lymph nodes, or discontinuous organs. All 32 patients received systemic chemotherapy. Fifteen (47%) underwent tumor debulking greater than 90% at diagnosis or during therapy. A complete or very good response to therapy occurred in 13 patients, and depended on surgical removal of bulk disease in all. Thirteen patients remained progression-free, but three of these patients died from treatment toxicity. Improved survival was correlated with a complete or very good partial response to multimodality therapy, surgical debulking of more than 90% either before or after chemotherapy, and use of the P6 protocol.

CONCLUSIONS

DSRCT is an aggressive cancer that occurs predominantly in young males. Improved survival is correlated with intense chemotherapy and aggressive resection.