Four Hospitals and a Giant Pelvic Tumour:
MDT-Guided Total Pelvic Exenteration for Extraskeletal Ewing Sarcoma in a 34-Year-Old Man

This article is a de-identified educational case review. It describes the clinical course of one patient managed at Beijing Arion Cancer Hospital and reflects the team's approach to multidisciplinary decision-making in a rare and highly aggressive pelvic tumour. It is not medical advice, nor does it guarantee outcomes for other patients. Treatment decisions must be individualized by qualified physicians.

Case Introduction

This issue reviews the full diagnostic and therapeutic course of a 34-year-old man with a giant, rapidly growing pelvic tumour. He had already been seen at four hospitals. Imaging and repeated pathology reviews converged on a high-grade small round cell tumour of undetermined type — a tumour whose precise classification could not be pinned down, leaving both chemotherapy and radiotherapy without a precise target. After six cycles of systemic therapy plateaued, the multidisciplinary team (MDT) at Beijing Arion Cancer Hospital judged that surgery was the key to breaking the deadlock and performed a total pelvic exenteration with urinary diversion and sigmoid colostomy. Final pathology confirmed extraskeletal Ewing sarcoma, and the patient was discharged smoothly three weeks after surgery to begin adjuvant therapy.

Core Conflict

The core conflict of this case was not a simple "race against life and death", but a standoff between two facts: the tumour was highly malignant and growing fast, yet its pathological type was undefined, so no more precise regimen could be designed. Systemic therapy had stalled, while several hospitals' surgical departments judged an operation too complex and too risky to attempt. The team had to decide whether to keep adjusting an already-exhausted chemotherapy plan, or to pursue a difficult and high-risk radical operation as the only realistic route to a breakthrough.

I. Case Overview: Baseline Status and Core Challenges

1. Baseline Status

Presentation: A 34-year-old man first sought care at a local county hospital for difficulty passing urine (dysuria). Ultrasound revealed a mixed-echo mass behind the bladder with two components measuring approximately 4.7 × 4.5 cm and 7.6 × 6.7 cm.

Imaging: Further MRI showed a cystic-solid occupying lesion in the seminal vesicle region, the larger component measuring about 5.4 × 5.0 × 6.1 cm, with enlarged surrounding lymph nodes and possible invasion of the prostate and the left obturator internus. He was referred to the Second Hospital of Hebei Medical University, where PET-CT showed cystic-solid masses in the bilateral seminal vesicle and prostate region measuring about 8.5 × 7.7 × 6.8 cm with increased uptake, indistinct from the lower rectum and the left obturator internus, with heterogeneous hypermetabolism and several surrounding hypermetabolic lymph nodes (the largest 1.0 × 0.8 cm). A solid nodule with hypermetabolism was also seen in the apical–posterior segment of the left upper lobe. The overall impression was a bilateral seminal vesicle and prostate malignant lesion invading the rectum and left obturator internus, with surrounding lymph-node and lung metastases considered likely.

Diagnostic basis: Percutaneous biopsy pathology suggested a mesenchymal-origin malignancy of uncertain type. Pathology consultation at several Beijing hospitals classified it as a small round cell tumour, but the specific type remained undefined; desmoplastic small round cell tumour, rhabdomyosarcoma, Ewing sarcoma and CIC sarcoma could not be excluded. Next-generation sequencing (NGS) was limited by the low cell yield and low nucleic-acid concentration, so only DNA-level analysis was completed: no EWSR1 rearrangement was detected and NKX2.2 was negative, yet Ewing sarcoma and CIC sarcoma still could not be ruled out. The patient then began six cycles of chemotherapy at a Beijing hospital (epirubicin 60 mg plus ifosfamide 12 g, every 3 weeks). Notably, the pelvic tumour had grown rapidly — only six weeks elapsed between detection and the start of chemotherapy — and by the time chemotherapy began the pelvic tumour volume had increased to 9.5 × 8.9 × 8.1 cm. By the time he presented to our hospital, he had already been through four hospitals.

2. Current Dilemma

Combining the patient's full diagnostic and treatment history with the imaging and pathology findings, the clinical team faced several difficult problems, and diagnosis and treatment had reached a deadlock:

First, the tumour was highly malignant, but its pathological type was undefined, so no more precise chemotherapy regimen could be formulated.

Second, on re-staging after the fourth cycle of treatment, there was no further response in the pelvic tumour, the lymph nodes or the lung metastases.

Third, medical oncology recommended transferring the patient to surgery, but several hospitals' surgical departments considered the operation complex and difficult and recommended adjusting the chemotherapy regimen and continuing systemic therapy — leaving a genuine disagreement over the treatment plan.

II. Decision-Making: MDT Core Analysis and Strategy Deliberation

1. Composition of the MDT Team

On receiving the patient, the hospital immediately activated its multidisciplinary collaboration mechanism, joining with Prof. Xi Zhijun (Department of Urology, Peking University First Hospital) and Prof. Sun Min (Hillman Cancer Center, University of Pittsburgh, USA). An MDT team was rapidly assembled, involving experts from the urologic oncology centre, the gastrointestinal oncology centre, the anesthesiology centre, the cancer rehabilitation centre, the radiation oncology centre, the intensive care unit and the nutrition department, aiming to achieve significant tumour response and restore the possibility of surgical debulking through precise assessment, individualized planning and stepwise treatment.

2. Assessment of Prior Treatment Response

Because the pathology review had not identified the cell of origin and no precise pathological classification could be defined, a generic regimen for mesenchymal malignant tumours — epirubicin plus ifosfamide for six cycles — had been chosen for the earlier treatment. Comparing imaging before and after chemotherapy: the lung nodule not only shrank markedly (from a maximum diameter of 1.3 cm before chemotherapy to 0.5 cm) but its metabolic activity disappeared completely; the multiple enlarged pelvic lymph nodes likewise shrank markedly, with metabolic activity essentially resolved; and the irregular mass in the prostate and seminal vesicle region shrank significantly, from an initial maximum cross-section of about 9.5 × 8.9 × 8.1 cm to a two-focus appearance after treatment (right focus about 2.2 × 1.5 cm, left focus about 1.8 × 1.8 cm), with a trend toward resolved metabolic activity — before treatment the whole lesion showed abnormally high uptake, whereas after treatment uptake fell markedly, with only focal increased metabolism in the left lesion. The overall assessment was partial response (PR).

3. Weighing the Treatment Pathways and Reaching a Decision

This patient had an exceptionally rare, unclassified, highly invasive small round cell tumour, combined with locally advanced disease and distant metastasis — a very complex situation. Constrained by the inability to reach a precise pathological diagnosis, further chemotherapy was unlikely to yield a clear benefit; and because different types of small round cell tumour differ substantially in radiosensitivity, a radiotherapy plan would also be difficult to design precisely. The MDT ultimately assessed that, given the tumour's high malignancy and the fact that chemo-radiotherapy had reached a deadlock, surgery was the key entry point to break through the current therapeutic impasse and the reasonable treatment strategy at this stage.

After the earlier six cycles of chemotherapy, the local pelvic anatomy had improved, and the conditions for preserving rectal function were more favourable than they had been at first diagnosis. However, the prognosis of different pathological types of small round cell tumour varies greatly; in particular, sarcoma of prostatic origin has an extremely poor prognosis and a very high risk of short-term local recurrence. A more aggressive surgical approach was therefore recommended: total pelvic exenteration plus urinary diversion, sigmoid colostomy, and postoperative chemo-radiotherapy.

But this operation carries enormous trauma and involves a complex anatomical field around the tumour: the risk of major intraoperative bleeding is high; the risk of postoperative abdominopelvic infection is high, with a substantial risk of bacteraemia and sepsis; gastrointestinal function recovers slowly, with possible ileus or even postoperative gastrointestinal bleeding; and the risk of postoperative thrombosis and even pulmonary embolism is high.

For this case, the MDT defined four core objectives: first, ensure adequate blood cross-matching, strictly control bleeding and maintain circulatory stability to create the basic conditions for surgery; second, correct electrolytes and improve the preoperative nutritional state; third, standardize the adjustment of bridging anticoagulant drugs to reduce the risk of arteriovenous thromboembolism and eliminate fatal postoperative complications; and fourth, after surgery, actively guide the patient to mobilize early and provide immediate nutritional risk assessment with intravenous and enteral nutritional management. Around these objectives, the team repeatedly rehearsed the surgical workflow and formulated a full-cycle risk plan covering preoperative conditioning, intraoperative contingency and postoperative rehabilitation.

III. The Breakthrough: Treatment Course and Technical Points

1. Overall Treatment Pathway

Preoperative adjustment of anticoagulant drugs and nutritional support → total pelvic exenteration → postoperative continuation of anticoagulant therapy, nutritional risk control and clinical observation → uneventful discharge three weeks after surgery.

2. In-Depth Analysis of the Key Steps

On the fifth day after admission, total pelvic exenteration with ileal conduit urinary diversion and sigmoid colostomy was formally started. Throughout the procedure the surgical and anesthesia teams coordinated closely, vital signs remained stable within the ideal range, and the operation was completed with an intraoperative blood loss of only 300 mL.

In the postoperative recovery phase, the team continued its "precision management" approach: the patient was observed in the intensive care unit for one day and then transferred smoothly back to the general ward; immediate intravenous nutrition and empirical anti-infection treatment were given; low-molecular-weight heparin subcutaneous anticoagulation was started promptly 12 hours after surgery; the patient mobilized at 24 hours after surgery; oral and enteral gastrointestinal nutrition was gradually restored from one week after surgery; and by two weeks after surgery all indicators met the discharge criteria and the patient was discharged in good condition with renewed hope for life. No severe complications such as ileus, abdominopelvic infection, bacteraemia or venous thrombosis occurred at any point during the perioperative period.

IV. Outcome Assessment and Follow-up Strategy

Pathology: Postoperative pathology confirmed a mesenchymal-origin malignancy of the prostate; combined with the immunohistochemistry results it was considered an extraskeletal Ewing sarcoma. Fibrous tissue proliferation with chronic inflammatory cell infiltration was seen between the tumour periphery and the deep muscularis propria of the rectum, and fibrous tissue proliferation with chronic inflammatory cell infiltration was also seen in the bilateral seminal vesicles, consistent with a post-treatment response. The urethral resection margin, both ureteral stumps and the rectal resection margin were all free of tumour. Bilateral internal iliac–obturator, external iliac, common iliac, presacral and perirectal lymph nodes all showed no tumour. The pathological stage was ypT2N0M1.

Follow-up strategy: The patient began adjuvant therapy six weeks after surgery with the VDC/IE chemotherapy regimen (17 cycles planned in total, including the six preoperative cycles); this is currently proceeding smoothly and is well tolerated. At three months of adjuvant treatment, a systematic re-evaluation is planned — particularly of the chemotherapy effect on the lung metastasis — and the feasibility of radiotherapy will be discussed. In addition, given the finding of MTAP copy loss on genomic testing, we recommend that, if the disease recurs or progresses in future, enrolment in a clinical study for MTAP-deleted solid tumours may be considered.

V. Insights from This Case

Reviewing the rescue of this patient with a rare, highly malignant pelvic small round cell tumour, the key to success lay in building on the MDT team as the cornerstone and quickly and accurately identifying the breakthrough point. The urologic oncology centre and the anesthesiology centre upheld a high professional standard and a sincere sense of physician responsibility, and, with outstanding expertise, successfully completed an extremely difficult and complex operation — breaking the deadlock and laying a solid foundation for the next stage of systemic therapy.

This case vividly illustrates the core value of MDT in the scientific diagnosis and treatment of complex tumours. From precise preoperative assessment, intraoperative risk control to scientific postoperative management, the discipline teams broke down professional barriers and collaborated efficiently — successfully carrying out debulking surgery while maximally controlling multiple potentially fatal perioperative risks — providing useful experience for the management of similar complex cases.

Expert Commentary

Prof. Bai Li

Chair of the Academic Committee and Chair of the Ethics Committee, Beijing Arion Cancer Hospital; Member of the International Committee on Intractable Tumours; formerly of the Department of Medical Oncology, First Medical Centre of the Chinese PLA General Hospital; Chief Physician, Professor

This article reports a rare, highly difficult and rapidly progressive pelvic small round cell malignancy (ultimately diagnosed as extraskeletal Ewing sarcoma) treated by multidisciplinary management. The case presented multiple clinical difficulties — difficulty in pathological diagnosis, rapid disease progression, concurrent lung metastasis, and extremely high surgical risk — and was ultimately managed through combined multidisciplinary diagnosis and treatment, precisely seizing the local-treatment window at the point of optimal tumour shrinkage after chemotherapy to complete a highly difficult total pelvic exenteration, with good perioperative control and confirmation of pathology followed by initiation of postoperative adjuvant therapy.

The case has five outstanding strengths, with very high clinical reference and teaching value:

1. High clinical educational and reference value: A giant primary pelvic mass whose pathology was undefined before surgery, postoperatively diagnosed on large-specimen pathology as extraskeletal Ewing sarcoma — an extremely uncommon presentation and a typical difficult case, offering strong reference value for the diagnosis and treatment of similar complex pelvic sarcomas.

2. Complete exposition of the diagnostic and therapeutic process with objective, detailed data: The article presents the entire pathway — from initial diagnosis, preoperative chemotherapy, MDT decision-making, high-difficulty surgery, perioperative management, postoperative pathological confirmation, postoperative adjuvant therapy and gene-guided long-term treatment. Treatment-effect records, imaging metabolic changes and postoperative recovery indicators are clear, forming a complete chain of evidence.

3. Clear MDT diagnostic and therapeutic logic with scientific decision-making: Pathology diagnosed a sarcoma before surgery but the specific type was not entirely clear; when a conventional sarcoma chemotherapy regimen achieved its best effect, the multidisciplinary team decisively broke through conservative-therapy thinking and, through joint multidisciplinary assessment of surgery or other local treatment, established a strategy of "surgical debulking plus subsequent systemic therapy", embodying the modern concept of precision oncology.

4. Outstanding surgical efficacy with systematic perioperative management: Under complex conditions — extensive tumour invasion, disordered anatomy and multiple prior cycles of chemotherapy — complete pelvic exenteration with urinary and intestinal reconstruction was achieved, with little intraoperative bleeding, no severe perioperative complications and excellent short-term recovery, demonstrating strong technical value.

5. Clear and well-structured case presentation: The report adopts the standard case-report framework of "case difficulty — decision-making deliberation — implementation process — lessons learned", with a fluent narrative and well-emphasized key points.