Characteristics and computed tomography evaluation of primary retroperitoneal tumours: report of 113 cases

The value of contrast-enhanced ultrasound in differentiating benign from malignant retroperitoneal masses

OBJECTIVES

To evaluate the value of contrast-enhanced ultrasound (CEUS) perfusion patterns in the differentiation of benign and malignant retroperitoneal masses (RMs).

METHODS

Between 2006 and 2023, 122 consecutive patients with an RM visualizable by B-mode US were investigated additionally with CEUS. On CEUS, the extent of enhancement (classified as marked, reduced, or absent) and the homogeneity of enhancement (HE; classified as homogeneous or inhomogeneous) were evaluated. Subsequently, the malignancy rate according to CEUS perfusion patterns was determined.

RESULTS

On CEUS, marked enhancement was significantly more frequently associated with malignancy than with benignity (p < 0.0001, Fisher's exact test). All lesions with no enhancement were benign. Regarding HE, there was no significant difference between benign and malignant lesions (p = 0.07, Fisher's exact test).

CONCLUSION

On CEUS, marked enhancement in an RM may be indicative of a malignant lesion. Furthermore, absent enhancement can be considered to be an indication of benignity. The use of CEUS can be helpful in the evaluation of the malignancy of retroperitoneal masses.

Mixed reality in primary retroperitoneal tumour surgery: Evaluation of preoperative and intraoperative application value

OBJECTIVE

To evaluate the feasibility and application value of mixed reality technology (MR) in Primary retroperitoneal tumour (PRT) surgery.

METHODS

From 276 patients who underwent PRT resection at the First Affiliated Hospital of Xi'an Jiaotong University, we screened 46 patients who underwent MR-assisted retroperitoneal tumour resection and 46 patients who underwent tumour resection without MR assistance. The intraoperative and postoperative recovery of the patients in both groups were compared, and the reliability and validity of the application of MR were further examined using the Likert scale.

RESULTS

There was a significant difference in the mean intraoperative bleeding volume between the two groups, but it was reduced in the MR group. The results of the Likert scale showed higher scores in the MR group than non-MR group.

CONCLUSIONS

MR can be used to assist PRT resection and has great potential to improve the rate of complete retroperitoneal tumour resection.

Preoperative contrast-enhanced CT-based radiomics nomogram for differentiating benign and malignant primary retroperitoneal tumors

OBJECTIVES

This study evaluated the ability of a preoperative contrast-enhanced CT (CECT)-based radiomics nomogram to differentiate benign and malignant primary retroperitoneal tumors (PRT).

METHODS

Images and data from 340 patients with pathologically confirmed PRT were randomly placed into training (n = 239) and validation sets (n = 101). Two radiologists independently analyzed all CT images and made measurements. Key characteristics were identified through least absolute shrinkage selection combined with four machine-learning classifiers (support vector machine, generalized linear model, random forest, and artificial neural network back propagation) to create a radiomics signature. Demographic data and CECT characteristics were analyzed to formulate a clinico-radiological model. Independent clinical variables were merged with the best-performing radiomics signature to develop a radiomics nomogram. The discrimination capacity and clinical value of three models were quantified by the area under the receiver operating characteristics (AUC), accuracy, and decision curve analysis.

RESULTS

The radiomics nomogram was able to consistently differentiate between benign and malignant PRT in the training and validation datasets, with AUCs of 0.923 and 0.907, respectively. Decision curve analysis manifested that the nomogram achieved higher clinical net benefits than did separate use of the radiomics signature and clinico-radiological model.

CONCLUSIONS

The preoperative nomogram is valuable for differentiating between benign and malignant PRT; it can also aid in treatment planning.

KEY POINTS

• A noninvasive and accurate preoperative determination of benign and malignant PRT is crucial to identifying suitable treatments and predicting disease prognosis. • Associating the radiomics signature with clinical factors facilitates differentiation of malignant from benign PRT with improved diagnostic efficacy (AUC) and accuracy from 0.772 to 0.907 and from 0.723 to 0.842, respectively, compared with the clinico-radiological model alone. • For some PRT with anatomically special locations and when biopsy is extremely difficult and risky, a radiomics nomogram may provide a promising preoperative alternative for distinguishing benignity and malignancy.

[Minimally invasive approach for the treatment of Giant retroperitoneal cystic tumors: Presentation of two cases and literature review]

The primary retroperitoneal tumors are malignant or no malignant neoplasias, which the mesenteric cyst has an uncommon presentation. They have a great histological variety that includes the simple lymphatic cysts or the lymphangiomas which are congenital or acquired tumors whose intra-abdominal localization is unusual. There are three clinical features: incidental, unspecific and acute; and their therapeutic management is determinate by their radiological profile and it involves the preoperative percutaneous drainage in case of huge cysts for decreasing the size of the tumor and getting the radical cystectomy without relapse. This review presents two cases of acute abdominal pain related to huge retroperitoneal cysts resolved by minimally invasive approach and bibliographic review.

Added value of contrast-enhanced ultrasound (CEUS) in the diagnosis of primary retroperitoneal serous adenocarcinoma: a case report

BACKGROUND

Primary retroperitoneal serous adenocarcinoma (PRSA) is a rare malignant disease. Given the rarity of the disease, the imaging features of PRSA are unclear. Contrast-enhanced ultrasound (CEUS) also plays an important role in the evaluation of the differential diagnosis of retroperitoneal lesions.

CASE PRESENTATION

We report the case of a 62-year-old woman of with increased CA125 levels for 1 year who was referred to our hospital. After conducting contrast-enhanced computed tomography and magnetic resonance imaging, the mass was misdiagnosed as a chocolate cyst. After transvaginal ultrasound (TUS) combined with CEUS, cystadenocarcinoma was considered as the initial diagnosis. Pathology results confirmed PRSA as the final diagnosis.

CONCLUSIONS

CEUS features of PRSA are reported for the first time based on this case, potentially aiding in the differential diagnosis of this rare entity before surgery.