Evaluation of cross-sectional imaging features that aid in the differentiation of benign and malignant splenic lesions

Differentiating malignant from benign splenic lesions: a meta-analysis and pictorial review of imaging features

OBJECTIVES

Splenic lesions might exhibit overlapping imaging features, varying from benign entities like cysts and hemangiomas to malignancies such as lymphoma and angiosarcoma. This meta-analysis aims to delineate imaging characteristics that distinguish malignant from benign splenic lesions.

METHODS

Adhering to PRISMA guidelines, we searched PubMed, Scopus, and Web of Science for studies on imaging features differentiating malignant from benign splenic lesions. We extracted data on splenic pathology and imaging characteristics and assessed the methodological quality via QUADAS-2. Odds ratio meta-analyses were performed using STATA (Version 17.0, Stata Corp, College Station, TX).

RESULTS

Portal phase hypoenhancement, hypovascular enhancement pattern, diffusion restriction, and late phase hypoenhancement, with odds ratios above 10, highly indicate malignancy. Other features suggestive of malignancy include solid morphology, lymphadenopathy, presence of perisplenic fluid, arterial hypoenhancement, hypoechogenicity on ultrasound, splenomegaly, and presence of multiple lesions. In contrast, cystic morphology, hypervascular-washout and hypervascular-persistent pattern of enhancement, late phase hyperenhancement, anechogenicity on ultrasound, portal phase hyperenhancement, well-defined borders, and calcification are in favour of benign pathology.

CONCLUSION

The study underscores the critical role of contrast-enhanced and diffusion-weighted imaging in distinguishing malignant from benign splenic lesions, emphasizing the role of features like portal phase hypoenhancement and restricted diffusion in diagnosing malignancies. Additionally, the study emphasizes the value of contrast-enhanced ultrasound, which allows for the visualization of key contrast-enhancement patterns without the risk of ionizing radiation exposure.

Diagnostic performance of different imaging modalities for splenic malignancies: A comparative meta-analysis

Background and objectives

The spleen hosts both benign and malignant lesions. Despite multiple imaging modalities, the distinction between these lesions poses a diagnostic challenge, marked by varying diagnostic accuracy levels across methods. In this study, we aimed to evaluate and compare the diagnostic performance of various imaging techniques for detecting malignant splenic lesions.

Methods

Following PRISMA guidelines, we searched PubMed, Scopus, and Web of Sciences databases for studies evaluating imaging techniques in detecting malignant splenic lesions. Data extraction included diagnostic accuracy metrics, and methodological quality was assessed using QUADAS-2. Diagnostic Test Accuracy meta-analyses were conducted using R (version: 4.2.1). Subgroup analyses and meta-regression were performed to compare different modalities and clinical settings.

Results

Our study included 28 studies (pooled sample size: 2358), primarily using retrospective designs with histopathology as the reference standard. PET scan demonstrated the highest diagnostic accuracy (AUC: 92 %), demonstrating a sensitivity of 93 % (95 % CI: 80.4 % - 97.7 %) and a specificity of 82.8 % (95 % CI: 71.1 % - 90.4 %). Contrast-enhanced ultrasound (CEUS), Contrast-enhanced CT scan, and contrast-enhanced MRI also showed impressive performance with AUCs of 91.4 %, 90.9 %, and 85.3 %, respectively. Differences among these modalities were not statistically significant, but they outperformed non-contrast-enhanced methods. PET and CEUS exhibited higher specificity for lymphoma cases compared to studies including other malignancies.

Conclusion and clinical implications

Overall, PET emerges as the best modality for splenic malignancies, and CEUS and CE-MRI show promise as potential alternatives, notably due to their reduced radiation exposure. Further research is essential for precise malignancy differentiation.

Incidental Focal Spleen Lesions: Integrated Imaging and Pattern Recognition Approach to the Differential Diagnosis

Spleen lesions and pseudolesions, detected incidentally in imaging, are not uncommon and may require further work-up. The imaging appearance of focal splenic lesions (FSLs) may not be pathognomonic, because of considerably overlapping features. Consequently, all imaging techniques lack specificity to fully characterize FSLs. Clinical correlation is mandatory, so as, first of all, to categorize the patient as having or not having a history of solid or hematologic malignancy. Nowadays, many patients have old imaging studies available for comparison and, consequently, it is important to understand if the lesion was previously present or not, and if the size is the same or has changed. In the absence of comparison studies, and with a lack of imaging features of benignity, further investigation may be necessary, using PET, biopsy, or short-term follow-up. Some algorithms have been proposed to manage incidental FSLs; however, none of these strategies has been validated by prospective studies to date. In this review we illustrate the topic of incidental FSLs and we analyze a number of published algorithms.

Two cases of splenic neoplasms with differing imaging findings that required laparoscopic resection for a definitive diagnosis

Introduction and importance

Splenic tumors are rare and are sometimes found incidentally. In such cases, laboratory tests and imaging studies should be performed based on the diagnostic algorithm to determine whether the tumor is benign or malignant. However, we clinicians sometimes encounter challenging cases. Herein we experienced two challenging cases of splenic tumor which we could not correctly diagnosis preoperatively.

Case presentation

Case 1: A female in her 80s presented to our surgical department to undergo follow-up examinations for Stage IIIa ascending colon cancer. A follow-up CT scan showed marked enlargement of the splenic tumor which suggested metastatic cancer. We performed laparoscopic splenectomy.

Case 2: A healthy female in her 50s presented to our internal medicine department to undergo a workup after multiple splenic tumors. A follow-up CT scan showed that the tumors had grown slightly. We could not completely rule out a malignant tumor. She rejected further follow-up study and chose splenectomy.

Clinical discussion

We experienced two cases of splenic hemangioma with different clinical presentations and imaging findings. Although some studies have reported that biopsying a splenic tumor is a safe and effective way of distinguishing among splenic tumors, in our country splenic biopsies are seldom performed due to fears of causing intraabdominal bleeding or tumor dissemination. Clinicians should consider whether it would be better to perform follow up with a biopsy or splenectomy as a definitive treatment on a case-by-case basis.

Conclusion

Laparoscopic splenectomy can be used for definitive management in cases involving malignancy or an uncertain etiology.

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Splenic tumors are sometimes challenging to be correctly diagnosed.

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We should recognize a diagnostic algorithm, but not always applicable.

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Clinicians should choose follow-up or splenectomy on a case-by-case basis.

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Splenectomy is the definitive management of malignancy or an uncertain etiology.