Intraabdominal Desmoplastic Small Round CellTumorsA Diagnostic and Therapeutic Challenge

Imran Hassan, M.D.1

Roman Shyyan, M.D.1

John H. Donohue, M.D.1

John H. Edmonson, M.D.2

Leonard L. Gunderson, M.D.3

Christopher R. Moir, M.D.1

Carola A.S. Arndt, M.D.4

Antonio G. Nascimento, M.D.5

Florencia G. Que, M.D.1

1 Department of Surgery, Mayo Clinic, Rochester,Minnesota.

2 Division of Medical Oncology, Mayo Clinic, Roch-ester, Minnesota.

3 Department of Radiation Oncology, Mayo Clinic,Scottsdale, Arizona.

4 Division of Pediatric Hematology and Oncology,Mayo Clinic, Rochester, Minnesota.

5 Department of Laboratory Medicine and Pathol-ogy, Mayo Clinic, Rochester, Minnesota.

Presented as a poster at the Annual Meeting of theAmerican Society of Clinical Oncology, May 2003,Chicago, Illinois, and published in abstract form inthe Annual Proceedings, 2003.

Address for reprints: Florencia G. Que, M.D., De-partment of Surgery, Mayo Clinic, 200 First StreetSouth West, Rochester, MN 55905; Fax: (507)284-5196; E-mail: que.florencia@mayo.edu

Received November 29, 2004; revision receivedMarch 24, 2005; accepted April 11, 2005.

BACKGROUND. Intraabdominal desmoplastic small round cell tumors (IDSRCT) are

uncommon but aggressive tumors that occur in young males. To the authors’

knowledge, only limited data are available on the natural history and optimal

treatment of this disease.

METHODS. The authors reviewed 12 patients with IDSRCT who were treated at their

institution between January 1991 and December 2001.

RESULTS. All patients were males, with a median age of 26 years. All patients were

symptomatic at the time of presentation, with a mean duration of symptoms of 2

months. Common presenting symptoms and signs were abdominal pain (67% of

patients), palpable abdominal mass (58% of patients), abdominal distension (42%

of patients), and hepatomegaly (33% of patients). Six patients (50%) had distant

metastases at presentation. Five patients underwent biopsy only. Surgical resection

was attempted in seven patients and included macroscopic total resection in three

patients and debulking in four patients. All of those patients subsequently devel-

oped recurrent or progressive disease, which required a second operation in six

patients. Overall, 6 patients (50%) developed symptomatic intestinal obstruction

requiring surgical management, and 3 patients (25%) developed ureteral obstruc-

tion. All 12 patients received multiagent chemotherapy. Seven patients (55%) also

received radiation therapy. The median survival of patients who underwent sur-

gical resection was 34 months, whereas the median survival of patients who

underwent biopsy alone was 14 months. One patient remained alive 72 months

after he underwent complete resection of primary and recurrent tumors, and 1

patient remained alive with disease 32 months after he underwent complete

resection of a primary tumor.

CONCLUSIONS. Patients with IDSRCT presented with a short duration of nonspe-

cific symptoms, and the disease was fatal almost uniformly, regardless of the

treatment modality used. Surgical resection may prolong survival in some patients.

Cancer 2005;104:1264 –70. © 2005 American Cancer Society.

KEYWORDS: intraabdominal desmoplastic small round cell tumors, surgery, che-motherapy, survival.

Desmoplastic small round cell tumors (DSRCT) belong to a groupof neoplasms known as small cell tumors, which predominantly

affect young males in their second and third decades of life.1,2 Theyoccur mainly in the abdomen and pelvis, although paratesticular,thoracic, and intracranial primary sites have been reported.3,4 Thesetumors have a tendency to spread along the peritoneum and me-sothelial-lined surfaces, with organ involvement an inconsistent andsecondary phenomenon. In the abdomen and pelvis, these tumorstypically present in an advanced stage with a bulky primary mass,

1264

© 2005 American Cancer SocietyDOI 10.1002/cncr.21282Published online 3 August 2005 in Wiley InterScience (www.interscience.wiley.com).

distant metastases, and peritoneal seeding. Tumorsthat present extraabdominally usually are less exten-sive.3 The histogenic origin of these tumors is unclear,although, because of its association with mesothelial-lined surfaces, it has been suggested that they arederived from the primitive mesothelium or subme-sothelial mesenchyme.2,3 Generally, these malignan-cies demonstrate the typical histologic features ofpoorly differentiated, small round, or spindle-shapedcells within a desmoplastic stroma.5 They are charac-terized further by a specific immunohistochemicalstaining profile with trilineage coexpression of inter-mediate-filament proteins, including epithelial mark-ers (cytokeratin and epithelial membrane antigen pos-itivity), mesenchymal markers (desmin and vimentinstaining), and neural markers (neuron-specific eno-lase reactivity).6 Genetic expression observed consis-tently in DSRCT reveals a unique reciprocal translo-cation t(11;22)(p13;q11 or q12), the result of fusion ofexon 7 of the Ewing sarcoma gene EWS on chromo-some 22 with exon 8 of the Wilms tumor suppressorgene WT1 on chromosome 11.6,7

Because most of our understanding regarding thepathologic and clinical nature of this disease has beenbased on case reports and small series of patients, thedevelopment of standard methods for its diagnosisand management has been difficult. Consequently, toour knowledge there is no clear consensus regardingthe optimal therapeutic modalities for treating thesehighly aggressive tumors. Herein, we present our ex-perience in the diagnosis and management of thisdisease at our institution.

MATERIALS AND METHODSBetween 1991 and 2001, 12 patients were diagnosedwith intraabdominal DSRCT (IDSRCT) and receivedthe majority of their treatment at the study institution.The diagnosis of IDSRCT was made based on patho-logic, immunohistochemical, and molecular analysisof tissue specimens, as described elsewhere.5 Patienthistories, including the surgeon’s operative notes,chemotherapy and radiation therapy records, and fol-low-up data, were reviewed for patient age, gender,presenting symptoms and duration, radiographic in-vestigations, type of surgery performed, postoperativecourse, adjuvant chemotherapy, radiation therapy,and follow-up.

Partial tumor regression was defined as a reduc-tion in all measurable tumors � 50%; progressive dis-ease was defined as tumor growth � 25% in volume orthe appearance of any new lesion. Macroscopic totalresection was defined as surgical resection of all mac-roscopically visible disease, debulking was defined asremoval of � 90% of the disease but with macroscop-

ically residual intraabdominal disease, and biopsy wasdefined as the removal of tissue for diagnosis only.The study was approved by the Institutional ReviewBoard.

RESULTSPatient Characteristics, Clinical Presentation,and DiagnosisAll patients were male. There were eight white pa-tients, two African-American patients, one Asian pa-tient, and one Hispanic patient. The median age at thetime of diagnosis was 26 years (range, 15– 41 yrs). Allpatients were symptomatic at the time of presentationwith a mean duration of symptoms of 2 months(range, from 1 wk to 9 mos). Abdominal pain (eightpatients), abdominal distension (five patients), palpa-ble abdominal mass (seven patients), and hepatomeg-aly (four patients) were the most common presentingsymptoms and signs. Computed tomographic (CT)scans were the most frequent diagnostic imaging mo-dality utilized (75%). The most common CT abnormal-ities were the presence of a pelvic mass (77%), retro-peritoneal and mesenteric lymphadenopathy (67%),and hepatic lesions (44%).

The tumor involved both the abdomen and pelvisin 5 patients (42%), occurred predominantly in thepelvis in 5 patients (42%), and diffusely involved peri-toneal surfaces without any dominant mass in 2 pa-tients (16%). Five patients (42%) had disease meta-static to the liver, and 1 patient (8%) had metastaticaxillary lymphadenopathy at presentation. Four pa-tients (33%) subsequently developed metastasis, in-cluding 2 patients with hepatic metastasis, 1 patientwith both pulmonary and osseous metastasis, and 1patient with osseous metastasis alone. Two patientsinitially were misdiagnosed with Hodgkin lymphomaand cecal adenoma, respectively, and were treatedelsewhere before their tumors were characterized cor-rectly.

Surgical TreatmentFive patients underwent biopsy only, because theirintraabdominal disease was too extensive for primarysurgical resection (Table 1). In the other seven pa-tients, a surgical resection was attempted. Primarymacroscopic total resection of disease was accom-plished in 3 of these patients, and the remaining 4patients underwent major (� 90%) debulking of theirintraabdominal disease. All patients who underwentmacroscopic total resection subsequently developedrecurrent or progressive disease, which required addi-tional surgery in six patients, including secondarymacroscopic total resection in two patients, debulking

Desmoplastic Small Round Cell Tumors/Hassan et al. 1265

in one patient, and palliative treatment for gastroin-testinal obstruction in three patients (Table 1).

Adjuvant Therapy in Patients who UnderwentSurgical ResectionThree patients (Table 1) received preoperative chemo-therapy with ifosfamide, mitomycin, doxorubicin, andcisplatin(IMAP)plusgranulocyte-macrophage– colony-stimulating factor (GM-CSF) and one patient receiveda combination of vincristine, doxorubicin, cyclophos-phamide, ifosfamide, and etoposide, which resulted in

partial tumor regression in three patients and a minorresponse in the one patient who received the latterregimen. One patient who received IMAP plus GM-CSF chemotherapy also received 4500 centigrays (cGy)of preoperative external beam radiation therapy(EBRT). These patients then underwent surgical resec-tion (macroscopic total resection in 1 patient and de-bulking in 3 patients) followed by adjuvant chemo-therapy plus EBRT (2800 cGy) to the abdomen andpelvis in 1 patient and postoperative chemotherapyalone in 3 patients. Subsequent disease progression/

TABLE 1Characteristics of the Patients who Underwent a Primary Surgical Resection

Patientage inyrs

Extent of disease atdiagnosis Preoperative therapy

Surgicaltherapy Postoperative therapy Outcome

Survival(mos)

27 Omental mass and pelvicmass

None Intraperitoneal P32;IMAP � GM-CSF

Recurrence at 36 mos with GTRof recurrent tumor afterpreoperative (4500 cGy) andintraoperative (1500cGy)radiation

Alive/NED(72)

18 Lower abdominal/pelvicmass

None GTR IMAP � GM-CSF Recurrence at 23 mos with GTRof recurrent tumor afterpreoperative (3960 cGy) andintraoperative (1500 cGy)radiation and P32; smallbowel obstruction at 4 mos;subsequent local and distantrecurrence 5 mos later

DOD (42)

22 Pelvic mass, liver andspleen metastasis,peritoneal and serosalimplants

IMAP (minorresponse);radiation (4500cGy)

GTR IMAP � GM-CSF Recurrence at 17 mos; nofurther surgery

Alive withdisease(32)

28 Lower abdominal/pelvicmass, peritoneal andomental implants

None Debulking IMAP � GM-CSF andradiation (5600cGy)

Disease progression with smallbowel obstruction at 26 mosrequiring diversion

DOD (36)

25 Lower abdominal/pelvicmass; peritoneal,serosal, and omentalimplants

IMAP � GM-CSF;(partial regression)

Debulking IMAP � GM-CSF Disease progression at 20 mos;biopsy only

DOD (34)

18 Pelvic mass; peritonealand serosal implants;retroperitonealimplants; livermetastasis,mediastinallymphadenopathy

Vincristine,doxorubicin,cyclophosphamide,ifosfamide,etoposide (partialregression)

Debulking Intraperitonealmitoxantrone,radiation (2800cGy), and intensivechemotherapy withperipheral celltransplantation

Disease progression withcolonic obstruction at 6 mosrequiring fecal diversion

DOD (10)

32 Peritoneal implants; livermetastases

IMAP (partialregression)

Debulking Intraperitoneal P32;IMAP � GM-CSF

Disease progression with smallbowel obstruction at 7 mosrequiring debulking; secondrecurrence with small bowelobstructio n 6 mos laterrequiring further debulking;renal insufficiency fromureteral obstruction

DOD (26)

GTR: macroscopic total resection; IMAP: ifosfamide, mitomycin, doxorubicin, and cisplatin; GM-CSF: granulocyte-macrophage– colony- stimulating factor; cGy: centigrays; NED: no evidence of disease; DOD: dead

of disease;.

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recurrence was observed in all 4 patients after a me-dian interval of 12 months (6 mos, 7 mos, 17mos, and20 mos, respectively).

Three other patients underwent primary surgicalexcision (macroscopic resection in two patients anddebulking in one patient) as initial treatment followedpostoperatively by IMAP plus GM-CSF in two patientsand IMAP alone in one patient. All 3 of these patientsalso developed progressive/recurrent disease after amedian of 26 months (23 mos, 26 mos, and 36 mos,respectively). The 2 patients with recurrent diseasewere treated with preoperative EBRT (4500 cGy and3960 cGy, respectively) followed by complete surgicalresection of their recurrent disease and intraoperativeradiation (1500 cGy) therapy. One patient was diseasefree 36 months after complete resection and preoper-ative and intraoperative irradiation for his recurrenttumor. The other patient developed local and distantdisease recurrence 4 months after the second tumorextirpation (Table 1).

Three patients received intraperitoneal P32 (IP32)(15 �C) as a part of their treatment regimen, including2 patients who received it after surgery for their pre-senting disease, which was comprised of macroscopicresection (local recurrence 36 mos after IP32) and de-bulking (disease progression 7 mos after IP32). Theother patient received IP32 after undergoing macro-scopic resection of recurrent disease (local and distant

recurrence 5 mos after IP32) (Table 1). One patientreceived intraperitoneal mitoxantrone at the time ofdebulking of the presenting disease followed by che-motherapy and an autologous peripheral blood celltransplantation (disease progression 6 mos after IP32)(Table 1).

Adjuvant Therapy in Patients who UnderwentBiopsy OnlyAll 5 patients who underwent a biopsy only (Table 2)began treatment with multiagent chemotherapy,which involved a 5-drug combination of vincristine,doxorubicin, cyclophosphamide, ifosfamide, and eto-poside in 2 patients; a 5-drug regimen (vincristine,doxorubicin, cyclophosphamide, etoposide, and cis-platin) plus external beam irradiation to the abdomenand pelvis (4500 cGy) in a third patient; and simplerdrug combinations in the other 2 patients (ifosfamideplus etoposide in 1 patient and etoposide, cisplatin,and doxorubicin in 1 patient). The three patients whoreceived the five-drug regimens experienced partialtumor regression, whereas disease progression wasobserved in the other two patients.

Outcome and SurvivalSix of 12 patients developed symptomatic intestinalobstruction during the course of their disease thatrequired surgical management, and 3 patients devel-

TABLE 2Characteristics of the Patients who Underwent Biopsy without Primary Surgical Resection

Patientage inyrs Extent of disease at diagnosis

Surgicaltherapy Postoperative therapy Response Outcome

Survival(mos)

27 Lower abdominal/retroperitonealand pelvic mass; periaorticlymphadenopathy;mediastinallymphadenopathy.

Biopsy Ifosfamide, etoposide Diseaseprogression

Colonic obstructionrequiringcolostomy

DOD (7)

32 Lower abdominal/retroperitonealand pelvic mass; peritonealimplants

Biopsy withpalliativebypass

Vincristine, doxorubicin,cyclophosphamide, etoposide,cisplatin, and EBRT (4500cGy)

Partial tumorregression

Ureteralobstruction.

DOD (4)

29 Pelvic mass; liver metastasis;retroperitoneal and paraaorticlymphadenopathy; osseousmetastasis

Biopsy Etoposide, cisplatin, doxorubicin Diseaseprogression

Ureteralobstruction.

DOD (21)

18 Pelvic mass; peritoneal disease;mesenteric, retroperitoneal,and pelvic lymphadenopathy

Biopsy Vincristine, doxorubicin,cyclophosphamide, etoposide,and ifosfamide

Partial tumorregression

DOD (36)

15 Peritoneal implants, livermetastasis

Biopsy Vincristine, doxorubicin,cyclophosphamide, etoposide,and ifosfamide

Partial tumorregression

DOD (14)

DOD: dead of disease; EBRT: external beam radiation therapy; cGy: centigrays.

Desmoplastic Small Round Cell Tumors/Hassan et al. 1267

oped renal insufficiency from ureteral obstruction thatrequired ureteral stents. Two patients were alive at lastfollow-up including 1 patient who survived 72 monthsafter macroscopic total resection of his primary tumorand remained free of his disease 36 months after com-plete resection and radiation therapy of his recurrenttumor. The other survivor was alive with disease 32months after complete macroscopic resection of hisprimary tumor. The median survival for patients whounderwent biopsy alone was 14 months, whereas themedian survival for patients who underwent surgicalresection was 34 months.

DISCUSSIONIn the current study, all the patients with IDSRCT weremen, with a median age of 26 years. Nine of the 12patients were between ages 10 years and 30 years, andthe other 3 patients were in their 40s. Others havereported the occurrence of this tumor in very youngchildren, in elderly patients, and in females.3,5 Recentmolecular and pathologic studies also have demon-strated significant histologic variability within thisfamily of tumors.2,3,5 Whether these differences repre-sent a spectrum of the disease or misdiagnosis willdepend on future reports that consistently utilize ac-curate immunohistochemical and molecular diagnos-tic techniques.

The most common presenting symptoms andsigns of IDSRCT (abdominal pain, distension, and apalpable abdominal mass) are nonspecific and nondi-agnostic. Although the mean duration of symptomsexperienced by our patients prior to diagnosis was 2months, 3 patients presented with acute symptoms ofabdominal pain and fever, including 1 patient whohad overt signs of peritonitis. CT scanning, the mostcommonly utilized diagnostic modality, revealed nocharacteristic findings for IDSRCT, merely evidence ofa disseminated intraabdominal malignancy. No ethnicpredisposition was apparent in the current series ofpatients. Our demographic and clinical data are sim-ilar to those reported previously,1,6,8 confirming thenonspecific clinical presentation of this disease.Therefore, it is important to consider IDSCRT as apossible diagnosis when a young man presents withnonspecific abdominal symptoms and radiographicevidence of a disseminated, intraabdominal malig-nancy.

Similar to previous reports,1,6,8 we found that ID-SRCT presented as a diffuse process within the abdo-men and pelvis without any apparent organ of origin.Ten of the 12 patients in the current study presentedwith a mass in the lower abdomen or pelvis as themain focus of disease along with additional peritonealimplants, which varied from a limited number of dis-

tinct nodules or plaques to innumerable peritonealimplants throughout the abdomen and pelvis. Twopatients had only diffuse peritoneal seeding without adominant mass. Hepatic metastasis was observed atthe time of presentation in five patients and developedsubsequently during the course of the disease in twoother patients. Skeletal metastasis occurred in twopatients, one of whom also developed pulmonary me-tastasis. Intraabdominal and retroperitoneal lymphnode involvement was noted in four patients, two ofwhom also had pathologically unconfirmed mediasti-nal lymphadenopathy. This pattern of disease spreadreveals the predilection of these tumors to metastasizethrough both lymphatic and hematogenous routes,making effective systemic therapy a necessity in treat-ing IDSRCT. Because of the tendency of IDSRCT toinvolve the peritoneal and serosal surfaces with des-moplastic implants during the course of disease, sev-eral of our patients eventually developed intestinalobstruction, which required either debulking with in-testinal resections or palliative bypass.

To our knowledge, no consensus has beenreached concerning the optimal strategy for managingIDSRCT. Furthermore, because of the heterogeneity ofthe therapeutic modalities utilized, it is difficult tocompare the efficacy and effectiveness of various reg-imens. The current study data also reflect the lack ofstandard therapy. However, the current literature1,6,8,9

and our results suggest that an aggressive approachinvolving total macroscopic tumor excision combinedwith chemotherapy and radiation may offer the bestopportunity for disease control and disease-free sur-vival. Because of the extensive involvement of thisdisease at the time of presentation, macroscopic re-section of the tumor often is unfeasible technically,although we would suggest that an attempt be madeto remove all macroscopic tumor. Primary completeor partial removal of macroscopic disease was possi-ble in only 60% of the patients in the current series butwas associated with a longer median survival. Al-though patients who underwent biopsy were morelikely to have extensive disease and did not respond totheir chemotherapy as well as the group of patientswho underwent attempted surgical resection, we be-lieve that extensive tumor reductive surgery may favorsurvival in this disease. The one patient in the currentseries who had long-term disease-free survival under-went macroscopic resection of both his primary andrecurrent tumors. Although to our knowledge only afew long-term survivors have been reported to date,the majority underwent macroscopic surgical resec-tion.1,8 Another important role of surgery in IDSRCT isthe relief of symptomatic gastrointestinal obstruction,

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which reportedly develops in half of the patients withthis disease.

IMAP plus GM-CSF; the chemotherapy regimen ofvincristine, doxorubicin, cyclophosphamide, ifosf-amide, and etoposide; and the less complex regimensall were found to be less than satisfactory therapy forIDSRCT. Although initial partial tumor regression wasreported in several patients, no permanent tumorcontrol was appreciated. Our observations are consis-tent with those reported from other institutions6,9,10

regarding the efficacy of chemotherapy patients within this disease. Farhat et al.10 reported one completeremission among five patients who were treated withcyclophosphamide, etoposide, doxorubicin, and cis-platin. In a review10 of 60 patients who were treated bychemotherapy with or without abdominal radiation,objective responses were noted in 17 patients, 8 ofwhom attained clinically complete tumor regressionstatus. The chemotherapeutic regimens associatedwith complete response were those that includeddoxorubicin, cyclophosphamide, vincristine, and cis-platin. Kushner et al.8 suggested that the transientfavorable response to chemotherapeutic agents notedin IDSRCT warrants attempts of consolidating diseaseregression using myeloablative chemotherapy withstem cell rescue. Recently, however, findings from aPhase II study11 with a high-dose chemotherapy regi-men of ifosfamide, epirubicin, and vincristine did notreport a significant improvement in survival in pa-tients with DSRCT. In a subsequent prospectivestudy,12 a similar regimen of high-dose chemotherapywas used along with autologous peripheral stem celltransplantation in conjunction with local treatment(surgery and/or radiotherapy). After a median follow-up of 35 months, the median overall survival in thatstudy was 14 months, leading the authors to concludethat high-dose chemotherapy did not alter the clinicalcourse significantly in these patients.12

Based on their experience, La Quaglia andBrennan4 from the Memorial Sloan-Kettering Can-cer Center have recommended adjuvant abdomi-nopelvic radiotherapy followed by surgery and che-motherapy. However, others have expressedconcern about the efficacy of radiation with thediffuse peritoneal involvement of this disease andthe potential toxicity to the adjacent organs, partic-ularly the small bowel.10 In their review of 21 pa-tients, Goodman et al.13 noted that patients whoreceived the institutional chemotherapy protocol(cyclophosphamide, doxorubicin, vincristine, ifosf-amide, and etoposide), followed by maximal surgi-cal debulking and consolidative radiation to the ab-domen and pelvis, had a better survival comparedwith contemporary reports. Although their patients

developed significant acute hematologic and gastro-intestinal toxicity, medically, they all were managedsuccessfully and completed their treatment course.The most common long-term complication wassmall bowel obstruction, which occurred in approx-imately one-third of the patients. Late side effects,however, are difficult to assess because many pa-tients develop complications from disease progres-sion or do not live long enough after radiation ther-apy to manifest treatment complications.

The tendency of these tumors to involve the sero-sal surfaces within the abdomen and pelvis and theexperience with pseudomyxoma peritonei was the ra-tionale behind using intraperitoneal agents in certainpatients. Although no significant impact was noted,the investigation of other potential intraperitonealchemotherapeutic agents appears feasible given theineffectiveness of systemically administered chemo-therapy.

IDSRCT is an uncommon neoplasm. With in-creased awareness and improvements in diagnosticcapabilities, more patients are likely to be diagnosedwith IDSRCT. Despite the currently preferred mul-timodality approach, including surgery, chemother-apy, and radiation therapy, the prognosis for pa-tients with this disease remains poor. Thedisseminated nature of the disease limits the effi-cacy of surgical therapy, making the development oftruly effective adjuvant therapies imperative. Per-haps genetically specific molecular therapy can bedeveloped for IDSRCT, similar to what has beenaccomplished for the treatment of gastrointestinalstromal tumors with imatinib.

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