Deep learning radiomics-based prediction model of metachronous distant metastasis following curative resection for retroperitoneal leiomyosarcoma: a bicentric study.

BACKGROUND: Combining conventional radiomics models with deep learning features can result in superior performance in predicting the prognosis of patients with tumors; however, this approach has never been evaluated for the prediction of metachronous distant metastasis (MDM) among patients with retroperitoneal leiomyosarcoma (RLS). Thus, the purpose of this study was to develop and validate a preoperative contrast-enhanced computed tomography (CECT)-based deep learning radiomics model for predicting the occurrence of MDM in patients with RLS undergoing complete surgical resection. METHODS: A total of 179 patients who had undergone surgery for the treatment of histologically confirmed RLS were retrospectively recruited from two tertiary sarcoma centers. Semantic segmentation features derived from a convolutional neural network deep learning model as well as conventional hand-crafted radiomics features were extracted from preoperative three-phase CECT images to quantify the sarcoma phenotypes. A conventional radiomics signature (RS) and a deep learning radiomics signature (DLRS) that incorporated hand-crafted radiomics and deep learning features were developed to predict the risk of MDM. Additionally, a deep learning radiomics nomogram (DLRN) was established to evaluate the incremental prognostic significance of the DLRS in combination with clinico-radiological predictors. RESULTS: The comparison of the area under the curve (AUC) values in the external validation set, as determined by the DeLong test, demonstrated that the integrated DLRN, DLRS, and RS models all exhibited superior predictive performance compared with that of the clinical model (AUC 0.786 [95% confidence interval 0.649-0.923] vs. 0.822 [0.692-0.952] vs. 0.733 [0.573-0.892] vs. 0.511 [0.359-0.662]; both P < 0.05). The decision curve analyses graphically indicated that utilizing the DLRN for risk stratification provided greater net benefits than those achieved using the DLRS, RS and clinical models. Good alignment with the calibration curve indicated that the DLRN also exhibited good performance. CONCLUSIONS: The novel CECT-based DLRN developed in this study demonstrated promising performance in the preoperative prediction of the risk of MDM following curative resection in patients with RLS. The DLRN, which outperformed the other three models, could provide valuable information for predicting surgical efficacy and tailoring individualized treatment plans in this patient population. TRIAL REGISTRATION: Not applicable.

Recurrence of locally invasive retroperitoneal dedifferentiated liposarcoma shortly after surgery: A case report and literature review.

RATIONALE: Retroperitoneal dedifferentiated liposarcoma (RPDDL) is an uncommon malignancy, which often remains undetected for many years due to having adequate space in the retroperitoneal cavity and lacking clinical manifestations in the early stage of the disease. Surgical procedure is usually used as the first choice for treatment. However, it is prone to local recurrence after the operation, resulting in an unfavorable prognosis. Our aim is to draw useful lessons from the new case and provide some experience for management of the disease. PATIENT CONCERNS: We describe a 55-year-old male patient who was admitted for a 3-week history of persistent dull ache of the left waist. A large mass of the left upper abdomen was palpated in physical examination. Moreover, the imaging examination revealed that the diameter of the mass was about 21 cm, and some adjacent vital organs were invaded, which brought great challenges to complete surgical resection. DIAGNOSIS: The postoperative pathological results confirmed that the mass was RPDDL with invasion of the surrounding vital structures including pancreas, spleen, left adrenal gland, left kidney, and vasculature with tumor emboli. INTERVENTIONS: Surgical resection of the mass was performed by our multidisciplinary team. The patient received chemotherapy 1 month after surgery. OUTCOMES: The effect of chemotherapy seemed to be unsatisfactory. Local multifocal recurrence of the tumor was considered about 2 months after surgery. Finally, he gave up any treatments and died of the disease. LESSONS: Regular physical examination and ultrasound screening may detect the disease as early as possible, especially for high-risk group aged 60 to 70, which should be popularized. Incomplete resection, vascular invasion, and interruption of postoperative treatment may lead to an unfavorable prognosis. Therefore, we think that patients with the disease may benefit from complete surgical resection and uninterrupted adjuvant therapy.

Influence of nutritional status and body composition on postoperative events and outcome in patients treated for primary localized retroperitoneal sarcoma.

BACKGROUND: Retroperitoneal sarcomas (RPS) are rare tumours of mesenchymal origin, commonly presented as a large tumour mass at time of diagnosis. We investigated the impact of body composition on outcome in patients operated on for primary localized RPS. PATIENTS AND METHODS: We retrospectively analysed data for all patients operated on for primary RPS at our institution between 1999 and 2020. Preoperative skeletal muscle area (SMA), visceral and subcutaneous adipose tissue area (VAT and SAT) and muscle radiation attenuation (MRA) were calculated using computed tomography scans at the level of third lumbar vertebra. European Working Group on Sarcopenia in Older People (EWGSOP2) criteria were applied to define myopenia. Using maximum log-rank statistic method we determined the optimal cut-off values of body composition parameters. Myosteatosis was defined based on determined MRA cut-offs. RESULTS: In total 58 patient were eligible for the study. With a median follow-up of 116 months, the estimated 5-year overall survival (OS) and local-recurrence free survival (LRFS) were 66.8% and 77.6%, respectively. Patients with myopenia had significantly lower 5-year OS compared to non-myopenic (p = 0.009). Skeletal muscle index and subcutaneous adipose tissue index predicted LRFS on univariate analysis (p = 0.052 and p = 0.039, respectively). In multivariate analysis high visceral-to-subcutaneous adipose tissue area ratio (VSR) independently predicted higher postoperative complication rate (89.2% vs. 10.8%, p = 0.008). Myosteatosis was associated with higher postoperative morbidity. CONCLUSIONS: Myopenia affected survival, but not postoperative outcome in RPS. Visceral obesity, VSR (> 0.26) and myosteatosis were associated with higher postoperative morbidity. VSR was better prognostic factor than VAT in RPS.

Percutaneous Microwave Ablation for Treatment of Retroperitoneal Tumors.

Purpose To determine if microwave ablation (MWA) of retroperitoneal tumors can safely provide high rates of local tumor control. Materials and Methods This retrospective study included 19 patients (median age, 65 years [range = 46-78 years]; 13 [68.4%] men and six [31.6%] women) with 29 retroperitoneal tumors treated over 22 MWA procedures. Hydrodissection (0.9% saline with 2% iohexol) was injected in 17 of 22 (77.3%) procedures to protect nontarget anatomy. The primary outcomes evaluated were local tumor progression (LTP) and complication rates. Oncologic outcomes, including overall survival (OS), progression-free survival (PFS), and treatment-free interval (TFI), were examined as secondary outcome measures. Results Median follow-up was 18 months (range = 0.5-113). Hydrodissection was successful in displacing nontarget anatomy in 16 of 17 (94.1%) procedures. The LTP rate was 3.4% (one of 29; 95% CI: 0.1, 17.8) per tumor and 5.3% (one of 19; 95% CI: 0.1, 26.0) per patient. The overall complication rate per patient was 15.8% (three of 19), including two minor complications and one major complication. The OS rate at 1, 2, and 3 years was 81.8%, 81.8%, and 72.7%, respectively, with a median OS estimated at greater than 7 years. There was no evidence of a difference in OS (P = .34) and PFS (P = .56) between patients with renal cell carcinoma (six of 19 [31.6%]) versus other tumors (13 of 19 [68.4%]) and patients treated with no evidence of disease (15 of 22 [68.2%]) versus patients with residual tumors (seven of 22 [31.8%]). Median TFI was 18 months (range = 0.5-108). Conclusion Treatment of retroperitoneal tumors with MWA combined with hydrodissection provided high rates of local control, prolonged systemic therapy-free intervals, and few serious complications. Keywords: Ablation Techniques (ie, Radiofrequency, Thermal, Chemical), Retroperitoneum, Microwave Ablation, Hydrodissection © RSNA, 2024.

Retroperitoneal liposarcoma: Case of a giant tumour inside the abdomen.

Retroperitoneal liposarcomas are rare malignant tumours that often grow rapidly in size and become symptomatic lat e in t he disease course, posing diagnostic a nd therapeutic challenges. Although abdominal imaging can rel iab ly diagnose the tumour, definitive diagnosis is only p ossib le th rough bio psy af ter surgical excision , w hich remains the primary treatment modality for these tumours. Long- term sur v ival is p rimarily determ ined throu gh histologic grade and post-resection tumour margins. We report t he case of a 43-year-o ld male patient, see n at Dr Ruth KM Pfau Hospital Karachi, who under went successful surgical excision for a well-differentiated retroperitoneal liposarcoma an d had no rad io gr aphic evidence o f local recurrence at both 3 and 12-month follow-ups.

Unusual presentation of biliopancreatic cancer as primary retroperitoneal tumor.

Primary retroperitoneal tumors are little-known neoplasias and consequently, difficult to diagnose. We report an extremely unusual case of a biliopancreatic adenocarcinoma with retroperitoneal localization simulating a primary retroperitoneal tumor. As far as we know, there are no similar cases published up to date.

An unusual case of retroperitoneal synovial sarcoma with CT, MRI, and F-18 FDG PET/CT findings.

Synovial sarcoma, predominantly found in the extremities, rarely occurs in the retroperitoneum. Tumors can often grow to a considerable size before diagnosis, which warrant the critical importance of early detection to minimize morbidity and mortality. While the final diagnosis relies on pathologic examination, imaging plays a crucial role in early detection.

Technique and Outcomes of Concomitant Aortic and Caval Resection and Reconstruction for Retroperitoneal Tumors.

BACKGROUND: Major vascular involvement is often considered a contraindication to resection of malignant tumors, but in highly selected patients, it can be performed safely, with results that are highly dependent upon the tumor biology. Resection of both the aorta and inferior vena cava (IVC) is a rare undertaking, requiring both favorable tumor biology and a patient fit for a substantial surgical insult; nevertheless, it provides the possibility of a cure. METHODS: Patients requiring resection and reconstruction of both the aorta and IVC from 2009 through 2019 at 2 university medical centers were included. Patient characteristics, operative technique, and outcomes were retrospectively collected. RESULTS: We identified 9 patients, all with infrarenal reconstruction or repair of the aorta and IVC. All cases were performed with systemic heparinization and required simultaneous aortic and caval cross-clamping for tumor resection. No temporary venous or arterial bypass was used. Since arterial reperfusion with the IVC clamped was poorly tolerated in 1 patient, venous reconstruction was typically completed first. Primary repair was performed in 1 patient, while 8 required replacements. In 2 patients, aortic homograft was used for replacement of both the aortoiliac and iliocaval segments in contaminated surgical fields. In the remaining 6, Dacron was used for arterial replacement; either Dacron (n = 2) or polytetrafluoroethylene (n = 4) were used for venous replacement. Patients were discharged after a median stay of 8 days (range: 5-16). At median follow-up of 17 months (range 3-79 months), 2 patients with paraganglioma and 1 patient with Leydig cell carcinoma had cancer recurrences. Venous reconstructions occluded in 3 patients (38%), although symptoms were minimal. One patient presented acutely with a thrombosed iliac artery limb and bilateral common iliac artery anastomotic stenoses, treated successfully with thrombolysis and stenting. CONCLUSIONS: Patients with tumor involving both the aorta and IVC can be successfully treated with resection and reconstruction. En bloc tumor resection, restoration of venous return before arterial reconstruction, and most importantly, careful patient selection, all contribute to positive outcomes in this otherwise incurable population.

Primary leiomyoma of the bladder radiologically mimicking a retroperitoneal tumor - a case report.

The case presented is of a 47-year-old patient with an extravesical pedunculated bladder leiomyoma, which was difficult to distinguish from a retroperitoneal tumor. Preoperatively, it was suspected to be a retroperitoneal tumor and a laparotomy with tumor resection was performed. lntraoperatively, the bladder and tumor were connected by a cord-like tissue. A retrospective review of preoperative images revealed that cord-like tissue, identified intraoperatively, was also present. Bladder leiomyomas can grow as extravesical pedunculated tumors. Therefore, when the continuity between the bladder and tumor is only a cord-like object, the finding ofcontinuity is useful to diagnose with bladder leiomyoma. J. Med. Invest. 70 : 513-515, August, 2023.

Resection of previously inoperable retroperitoneal liposarcoma.

We present a case of successful resection of a large right upper quadrant retroperitoneal dedifferentiated liposarcoma involving multiple adjacent organs, initially considered inoperable in a patient in his 40s. This case highlights the importance of extensive preoperative planning and a multidisciplinary approach in achieving a greater chance of curative resection. Preoperative optimisation included neoadjuvant chemotherapy, concurrent portal vein embolisation and hepatic vein embolisation. The patient then underwent en-bloc resection, including total pancreatectomy, hemihepatectomy and vena caval resection in conjunction with extracorporeal membrane oxygenation and percutaneous venovenous bypass.

Incidentally detected retroperitoneal paraganglioma in a 10-year-old French bulldog.

This article reports a case of a 10-year-old French bulldog initially seen for reluctance to move and episodes of pain. A magnetic resonance imaging study was undertaken in order to rule out a herniated disc. A large, retroperitoneal mass was visualized and cytological analysis suggested a neoplastic proliferation. The mass appeared to compress the caudal vena cava when viewed by abdominal CT scan. The mass was surgically removed. A nephrectomy was also carried out and aortic bleeding identified after dissection of adhesions. Despite these complications, the dog did well after the procedures. Postoperative checkups were normal. Histological and immunohistochemical analyses of the mass were compatible with a retroperitoneal paraganglioma. Key clinical message: This type of tumor is poorly described in the veterinary literature. As the behavior of this tumor type is not yet fully understood, each new description adds to our knowledge and should help in diagnosing and treating it more effectively in the future.

Paragangliome rétropéritonéal de découverte fortuite chez un bouledogue Français de 10 ans. Cet article expose le cas d'un chien mâle entier bouledogue Français de 10 ans présenté initialement pour des difficultés locomotrices et des manifestations algiques. Un examen d'imagerie par résonnance magnétique (IRM) est rapidement réalisé afin d'explorer l'hypothèse d'une hernie discale. Une volumineuse masse rétropéritonéale est alors mise en évidence. L'analyse cytologique de cette dernière est compatible avec un processus néoplasique. Après la réalisation d'un examen par tomodensitométrie de l'abdomen et la mise en évidence d'une compression marquée de la veine cave caudale par la masse, une prise en charge chirurgicale avec exérèse de la masse est décidée. Lors de l'intervention chirurgicale une néphrectomie est réalisée et un saignement aortique est identifié après la dissection des adhérences. Malgré ces complications, le chien se réveille bien et les contrôles post opératoires effectués sont satisfaisants. Les analyses histologiques et immunohistochimiques de la masse seront en faveur d'un paragangliome rétropéritonéal extra surrénalien.Message clinique clé :Ce type tumoral fait l'objet de peu de descriptions dans la littérature vétérinaire. Toute la lumière n'a pas encore été faite sur son comportement et chaque nouvelle description permet d'en enrichir les connaissances et donc de mieux comprendre ce type tumoral, ce qui, à l'avenir, pourra aider à le diagnostiquer plus facilement et à le traiter plus efficacement.(Traduit par les auteurs).

Preoperative differentiation of mediastinum and retroperitoneum ganglioneuroma from schwannoma with clinical data and enhanced CT: developing a multivariable prediction model.

AIM: To develop a multivariable prediction model for preoperative differentiation of ganglioneuroma (GN) from schwannoma in mediastinum and retroperitoneum based on clinical data and enhanced computed tomography (CT). MATERIALS AND METHODS: This was a retrospective diagnostic study. Patients diagnosed with mediastinum or retroperitoneal GN or schwannoma at Zhongshan Hospital between July 2006 and March 2022 were divided into a training cohort and a validation cohort at a ratio of 7:3. Clinical information and CT features were collected. Histopathology was the reference standard for diagnosis. The model was developed using binary logistic regression. The predictive performance of the model was assessed using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). RESULTS: A total of 105 patients (47 men and 58 women; mean age of 41 ± 15 years) were enrolled. There were significant differences in symptoms (p=0.006), location (p=0.008), ratio of the craniocaudal diameter (CC) to the major axis on axial images (CC/M; p=0.025), ratio of the CC to the diameter on axial images (CC/D; p<0.001), density homogeneity (p=0.001), enhancement homogeneity (p<0.001), enhancement degree (p<0.001), venous phase CT attenuation value (V; p=0.011), and blood vessels changes (p=0.045) between GN and schwannoma. The area under the ROC curve (AUC) and accuracy in the validation cohort were 0.841 (95% confidence interval [CI] 0.672, 1.000) and 0.839 (95% CI: 0.674, 0.929), respectively. Calibration curves and DCA showed that the model was beneficial for patients. CONCLUSION: The multivariable prediction model exhibited good predictive performance and may facilitate preoperative planning.

Clinician survey of current global practice for sarcoma surveillance following resection of primary retroperitoneal, abdominal, and pelvic sarcoma.

INTRODUCTION: - Postoperative surveillance following resection of primary retroperitoneal, abdominal, and pelvic sarcoma (RPS) is standard of care in international sarcoma centres and has rapidly evolved without an evidence base to become highly intensive and prolonged. This clinician survey aims to capture a global, contemporary snapshot of international guidelines used to inform sarcoma surveillance following resection of primary RPS. MATERIALS AND METHODS: - Between July 2022 and March 2023, an online, anonymous, clinician survey to assess the current duration, imaging intervals and imaging modalities used for postoperative surveillance following resection of primary RPS was distributed among clinicians working at centres which are members of the TransAtlantic Australasian Retroperitoneal Working Group (TARPSWG). RESULTS: - Responses were received from 58 different TARPSWG centres. The majority of centres use institutional guidelines to guide surveillance intensity (n = 43, 74%) and the surveillance imaging modality (n = 39, 67%) used. For surveillance intensity and imaging modality, institutional guidelines are partially or entirely based on international guidelines in 81% (n = 47) and 78% (n = 45) of centres, respectively. Commonly used imaging modalities are contrast-enhanced CT abdomen-pelvis (n = 51, 88%) for abdominal surveillance and non-contrast enhanced CT (n = 25, 43%) for chest surveillance. Imaging intervals, timing of de-escalation of imaging frequency and total duration of surveillance for low-grade and high-grade RPS are reported. CONCLUSION: - This global survey among TARPSWG members demonstrates the heterogeneity in sarcoma surveillance strategies worldwide and emphasises the need for a randomised controlled trial to provide an evidence base for the optimal surveillance schedule following primary resection of RPS.