Vascular disease of the spleen

Multimodality Imaging Features of Various Splenic Lesions: Clinical and Histopathologic Correlation

The spleen is occasionally referred to as the 'forgotten organ' because splenic lesions are less common and encountered rarely compared to pathologies of other abdominal solid organs. Therefore, although well-demonstrated using various abdominal imaging modalities, radiologists tend to be less familiar with splenic diseases, making interpretation challenging. This study aimed to review common and uncommon splenic diseases and illustrate the multimodal imaging (including ultrasonography, CT, MRI, and PET/CT) features of these lesions in correlation with their histopathology. Recognizing the radiological findings of various splenic lesions helps narrow down the differential diagnosis and guide appropriate clinical decision-making for radiologists.

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.

Multimodality ultrasound assessment of the spleen: Normal appearances and emergency abnormalities

This paper summarizes the main splenic emergencies and their ultrasonographic findings to orient appropriate patient management. US requires minimal preparation time and allows to examine the parenchyma and to detect intraperitoneal fluid collections, which may be indirect evidence of solid organ injuries. In this paper, we analyze the role of B-mode, Doppler and Contrast-Enhanced Ultrasound in the diagnosis of splenic emergencies, with a particular focus on splenic infarction, infection, traumatic injuries and vascular splenic anomalies.

Differential Diagnosis of Cystic Lesions of the Spleen: A Review of Clinical, Imaging and Pathological Findings

Cystic lesions of the spleen are being noticed with increased frequency as "incidentalomas" during imaging work-up for unrelated causes. As a group, these lesions encompass pure cystic and mixed cystic and solid, benign and malignant processes that in general require a tissue sample for definitive diagnosis. In this review, we will describe the differential diagnosis of cystic lesions of the spleen, highlighting key imaging, clinical and pathologic findings.

Early Thrombosis of Splenic Artery Stent Graft

Splenic artery aneurysms (SAAs) are among the most common visceral aneurysms behind aortic and iliac arteries. Certain factors like aneurysm size (especially giant SAAs), hypertension (HTN), symptomatology, pregnancy, portal hypertension (pHTN), and liver transplantation increase the risk of rupture. Most often found incidentally, but when symptomatic, can present with nonspecific symptoms like nausea, vomiting, anorexia, and epigastric/left upper quadrant pain. Diagnosis can be accomplished with different modalities of CT or MRI and digital subtraction angiography (DSA) being the gold standard for diagnosis. Treatment is usually preferred for aneurysms >2 cm, symptomatic cases, and pregnant women. Various surgical/interventional procedures can be performed and selected based on the patient’s sex, age, location of the aneurysm, size of the aneurysm, and presenting complaints/complications. Endovascular techniques with or without stent-graft placement are being used more, given the minimally invasive nature of these procedures. No clear guidelines exist on initiation of dual antiplatelet therapy (DAPT), but based on guidelines from visceral arterial stenting (especially iliac arteries and renal arteries), multiple case reports/series on SAAs, we highly recommend the usage of DAPT pre- and post-stent-graft placement to improve patency.

A Cadaveric Study of Splenic Fissures and Bilobed Spleen

Objectives

Anatomical knowledge regarding the external morphology of the spleen is essential for surgical intervention and radiological diagnosis. A characteristic feature of the spleen is the presence of splenic notches at the superior border; however, such notches rarely extend deep enough to be considered fissures or to separate the spleen into multiple lobes. To date, there are very few cadaveric reports of splenic fissures. This study aimed to examine the anatomy and morphological structure of spleens collected from cadavers in order to identify the prevalence and clinical significance of splenic notches, fissures and lobation.

Methods

This study was conducted at the Department of Anatomy, Katuri Medical College and Hospital, Guntur, Andhra Pradesh, India. A total of 50 spleens were collected from cadavers over a period of seven years from 2012-2019 and examined to determine the presence of splenic notches or fissures.

Results

Of the 50 spleens, 40% had notches at the superior border, 10% had notches at the inferior border and 50% had no notches at either border. Fissures were present in five spleens (10%); of these, three showed incomplete fissures and the remaining two had complete fissures that divided the spleen into two lobes.

Conclusion

The findings of this study provide valuable information regarding the anatomy and prevalence of splenic fissures and bilobed spleens. A bilobed spleen is a rare congenital malformation which should be considered distinct from other known splenic anomalies. The presence of splenic fissures in bilobed spleens can serve as a guide for surgeons during conservatory splenectomy procedures.

Visceral Artery Aneurysms: Diagnosis, Surveillance, and Treatment

Visceral artery aneurysms (VAAs) are a rare, but serious clinical entity as rupture confers a high rate of mortality. Data regarding the prevalence, treatment, and prognosis of VAAs is largely from case series, as true randomized trials are lacking. The incidence of VAAs has risen over the decades with advances in imaging technology, availability, and utilization. Even in the presence of symptoms, the prompt diagnosis of VAAs may be challenging as symptoms are often nonspecific and varied. Although there are no definitive treatment guidelines, asymptomatic VAAs require treatment in the following scenarios: when the aneurysm diameter is greater than 2 cm, when identified during pregnancy, when multiple aneurysms are present, and in the case of hepatic transplant. Similar to therapeutic trends in other vascular beds, advances in endovascular devices and techniques have driven an "endovascular first" approach for the treatment of VAAs. However, although the success rates of endovascular repair are impressive, surgical intervention is still necessary in treating centers. This paper reviews the pathophysiology, clinical features, anatomic characteristics, and management strategies required for the effective diagnosis and treatment of VAAs.

Vascular Diseases of the Spleen: A Review

Vascular diseases of the spleen are relatively uncommon in the clinical practice. However, the reported incidence has been progressively increasing, probably due to advances in the imaging modalities used to detect them. This disease condition often presents with non-specific clinical manifestations, but can be associated with significant morbidity and mortality. This review article aims to provide updated clinical information on the different vascular diseases of the splenic vasculature-splenic vein thrombosis, splenic vein aneurysm, splenic artery aneurysm, splenic arteriovenous fistula, and spontaneous splenorenal shunt-in order to aid clinicians in early diagnosis and management.

Imaging of the spleen: what the clinician needs to know

The spleen is considered 'the forgotten organ' among radiologists and clinicians, although it is well visualised on abdominal computed tomography and magnetic resonance imaging. Moreover, the spleen is commonly involved in a wide range of pathologic disorders. These include congenital anomalies, infectious and inflammatory diseases, vascular disorders, benign and malignant tumours, and systemic disorders. In this review, we focus on the key imaging findings of the normal spleen, its variants, as well as relevant congenital and acquired abnormalities. It is of utmost importance to recognise and correctly interpret the variable spectrum of abnormalities that may involve the spleen, in order to avoid unnecessary invasive procedures and to guide adequate treatment.

Computed tomography of the spleen: how to interpret the hypodense lesion

Background

As the largest single lymphatic organ in the human body, the spleen is responsible for central immunological and haematological tasks. Therefore, the spleen can be subject to a wide range of pathologic disorders. Computed tomography (CT) represents the most widely applied cross-sectional abdominal imaging technique and is considered the imaging modality of choice for the evaluation of numerous abdominal pathological conditions. Hypodense splenic lesions are frequently encountered on abdominal CT images. Although most hypodense lesions of the spleen can be considered benign, some findings and clinical conditions warrant closer attention to the lesion. CT offers a number of morphological criteria that can be applied to differentiate hypodense lesions of the spleen, such as a the appearance of a lesion’s borders, its attenuation, as well as the presence of calcifications or solid components.

Methods

This article reviews the most common splenic pathologies leading to hypodense appearances on CT images and illustrates the key CT imaging findings in the context of the clinical history of the patients.

Conclusion

The key imaging findings of hypodense splenic lesions are presented in order to aid interpretation during routine evaluation of abdominal CT images.

Teaching Points

• Haemangiomas, congenital in origin, represent the most common benign lesions of the spleen.

• Lymphoma represents the most common malignant tumour of the, usually secondarily involved, spleen.

• Most hypodense splenic lesions on CT represent benign lesions that require no further work-up.

• For correct interpretation, hypodense splenic lesions need to be evaluated in the clinical context.

Melena-associated regional portal hypertension caused by splenic arteriovenous fistula

Regional portal hypertension is a rare cause of upper gastrointestinal bleeding. We reported an extremely rare case in which regional portal hypertension was associated with both the splenic arteriovenous fistula and chronic pancreatitis. In June 2010, our patient, a 41-year-old man, was admitted to a local hospital due to a sudden melena and dizziness without haematemesis and jaundice. The splenic arteriovenous fistula in this patient was successfully occluded through transcatheter arterial embolization. At the 12-mo follow-up, our patient was in good condition.

Unusual CT and MR Imaging Characteristics of Splenic Lymphoma

Lymphoma is the most common malignancy of the spleen. The imaging features of splenic lymphoma are nonspecific and mostly lymphomas present as a diffusely enlarged spleen. Focal lesions are described but remain of low density or intensity on CT or MRI, respectively. We describe a histologically proven case of splenic lymphoma that showed an atypical hyperdense/hyperenhancing appearance on imaging suspicious for a vascular pathology. To the best of our knowledge and based on review of English literature, such an appearance of splenic lymphoma is extremely unusual and rare.

[Tortuosity and calcification of the splenic artery. More than an additional finding]

Tortuosity of the splenic artery and calcification of the vessel wall are typical additional findings on plain abdominal x-ray. The combination of both anomalies is common in elderly persons presenting without symptoms of splenic ischemia. Its pathogenesis is thought to be multifactorial. In infancy and childhood, the splenic artery is stretched in its entire course. A growing difference between the length of the vessel and the distance between its origin and the splenic hilum gives rise to tortuosity. The artery's proximal segment is involved more frequently and more severely than the distal one. The tortuous route of the vessel is accentuated by the direction of its major branches, which is roughly perpendicular to the main trajectory. Neither tortuosity nor calcification should be taken to be risk factors for the comparatively common splenic artery aneurysm. Calcific deposits are not confined to the media but are also detected in the intima of the vascular wall. Critical narrowings of the lumen arising on the calcium deposits are not observed. Calcifying atherosclerosis of the splenic artery is comparable to medial sclerosis of the peripheral arteries frequently noticed in diabetics and dialysis patients. Only the less important calcification of the intima may be attributed to mechanisms of the hydrohemodynamic theory of atherosclerosis. The spleen's blood storage capacity may contribute to the characteristic age-dependent alterations of the shape and course of the splenic artery.