Vascular Diseases of the Spleen: A Review

New insights on extramedullary granulopoiesis and neutrophil heterogeneity in the spleen and its importance in disease

Neutrophils are traditionally viewed as uncomplicated exterminators that arrive quickly at sites of infection, kill pathogens, and then expire. However, recent studies employing modern transcriptomics coupled with novel imaging modalities have discovered that neutrophils exhibit significant heterogeneity within organs and have complex functional roles ranging from tissue homeostasis to cancer and chronic pathologies. This has revised the view that neutrophils are simplistic butchers, and there has been a resurgent interest in neutrophils. The spleen was described as a granulopoietic organ more than 4 decades ago, and studies indicate that neutrophils are briefly retained in the spleen before returning to circulation after proliferation. Transcriptomic studies have discovered that splenic neutrophils are heterogeneous and distinct compared with those in blood. This suggests that a unique hematopoietic niche exists in the splenic microenvironment, i.e., capable of programming neutrophils in the spleen. During severe systemic inflammation with an increased need of neutrophils, the spleen can adapt by producing neutrophils through emergency granulopoiesis. In this review, we describe the structure and microanatomy of the spleen and examine how cells within the splenic microenvironment help to regulate splenic granulopoiesis. A focus is placed on exploring the increase in splenic granulopoiesis to meet host needs during infection and inflammation. Emerging technologies such as single-cell RNA sequencing, which provide valuable insight into splenic neutrophil development and heterogeneity, are also discussed. Finally, we examine how tumors subvert this natural pathway in the spleen to generate granulocytic suppressor cells to promote tumor growth.

Vascular complications of chronic pancreatitis and its management

Chronic pancreatitis is a chronic fibro-inflammatory disorder of the pancreas, resulting in recurrent abdominal pain, diabetes mellitus, and malnutrition. It may lead to various other complications such as pseudocyst formation, benign biliary stricture, gastric outlet obstruction; and vascular complications like venous thrombosis, variceal and pseudoaneurysmal bleed. Development of varices is usually due to chronic venous thrombosis with collateral formation and variceal bleeding can easily be tackled by endoscopic therapy. Pseudoaneurysmal bleed can be catastrophic and requires radiological interventions including digital subtraction angiography followed by endovascular obliteration, or sometimes with a percutaneous or an endoscopic ultrasound-guided approach in technically difficult situations. Procedure-related bleed is usually venous and mostly managed conservatively. Procedure-related arterial bleed, however, may require radiological interventions.

Imaging patterns in non-traumatic spleen lesions in adults-a review

The spleen is a complex organ involved in multiple physiological processes in the human body. Elective splenectomy is an uncommon operation, and the precise characterization of the lesion should be achieved to determine the risks and benefits of this operation accurately. Given the significant role of the spleen in homeostasis and the potential risks of the surgery itself and following sequelae such as infection susceptibility, accurate recognition, and classification of splenic lesions is required before surgery. This review provides an overview of malignant (e.g., lymphoma, angiosarcoma) and benign (e.g., cysts, hemangioma, hamartoma) splenic lesions that may warrant an elective splenectomy. Images from a cohort of adult patients undergoing isolated splenectomy for non-traumatic indications in a single center are provided. This review highlights the considerable overlap in imaging patterns between splenic lesions, splenic lesions masquerading as lesions in other organs, increased detection of asymptomatic splenic incidentalomas due to improvements in imaging modalities. This review also provides clinical correlations for each lesion, providing additional information to help clinicians differentiate between lesions and accurately identify diseases amenable to surgical management.

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.

Acute Pancreatitis Induced Splenic Vein Thrombosis

Acute inflammation of the pancreas, known as pancreatitis, can result in many complications ranging from acute distress respiratory syndrome to pancreatic necrosis. A relatively common vascular complication of pancreatitis is splenic vein thrombosis (SVT) due to intimal inflammation leading to platelet aggregation and thrombosis. The management of SVT with regard to anticoagulation (AC) might appear to be perplexing at first given the recommendation to withhold any sort of AC. Research studies have shown that these patients have an increased risk of gastrointestinal bleeding without AC. In this report, we discuss a case of hypertriglyceridemia-induced pancreatitis. During hospitalization, our patient complained of worsening abdominal pain with objective fevers and leukocytosis in which CT scan of the abdomen was significant for hemorrhagic pancreatitis with necrosis, acute SVT, and splenomegaly. The patient was managed conservatively with IV fluids, pain relief medications, and antibiotics. 

A review of anatomy, pathology, and disease spread in the perisplenic region

The perisplenic region is a complex anatomical area involving multiple peritoneal and subperitoneal structures, which influence the presentation and behavior of various pathologic processes. This review is a comprehensive resource for perisplenic anatomy and pathology with associated clinical presentations and imaging findings. Understanding the pathophysiologic intricacies of the perisplenic region assists the radiologist in building a helpful differential diagnosis and recognizing predictable disease patterns.

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.

Decision-making and therapeutic options in intact splenic artery aneurysms: single-center experience and literature review

BACKGROUND

Splenic artery aneurysms are rare, potentially serious, and usually asymptomatic. Several methods are currently available to treat them, each with their own advantages and drawbacks. Therefore, its therapeutic paradigm has changed.

METHODS

We review our database of splenic aneurysms (2009-2019) and undertake an exhaustive literature review. Demographic, clinical, diagnostic, therapeutic, early and follow-up outcome data were examined. Our experience comprised: 15 patients with 19 splenic aneurysms. 11 women (average age, 59.4 years) and 4 men (average age, 61.7 years). All asymptomatic.

RESULTS

At diagnosis, aneurysms had a mean cross-sectional diameter of 3.4 cm (3.2 and 3.9 for women and men, respectively), the largest measuring 8.5 cm. Two independent aneurysms were detected in four patients. Diagnoses were always incidental to a CT scan. Treatments consisted of open surgery (2 patients), endovascular surgery (10 patients: 7 embolizations, 3 covered stent) and observation/follow-up (3 patients). The cases of open surgery (with splenectomy) were carried out without postoperative morbidity. One embolization failed (requiring subsequent open surgery) and two suffered localized splenic infarction, but without further complications. In patients treated with a covered stent, the aneurysm was always excluded, without complications. There was no 30-day or follow-up (average 26.2 months) mortality. Splenic aneurysms are diagnosed more frequently and earlier (in the asymptomatic phase), albeit incidentally, than in the past.

CONCLUSIONS

The correct indication (identifying patients at risk) and individualization of treatment, in which endovascular techniques are the first-line option, have significantly improved morbidity and mortality outcomes in our hospital.

A case of acute splenic vein thrombosis in a dog

An 11-year-old, castrated male, Yorkshire Terrier was presented with acute vomiting after chicken bone ingestion. The dog had been diagnosed with hyperadrenocorticism previously and showed acute splenomegaly and signs of systemic inflammatory response syndrome during hospitalization. On diagnostic imaging, acute splenic vein thrombosis was found, concurrent with pancreatitis and gastritis. The spleen showed marked enlargement and hypoechoic lacy appearances on ultrasonography, mimicking splenic torsion. On the histopathologic report, only splenic hemorrhage and congestion with large splenic vein thrombosis were identified. After splenectomy, the dog completely recovered and was discharged.

Spontaneous rupture of a splenic artery aneurysm with splenic epithelioid hemangioendothelioma: a case report

Spontaneous rupture of a splenic artery aneurysm with splenic epithelioid hemangioendothelioma is a rare condition. Splenic artery aneurysm can be complicated by rupture resulting in hypovolemic shock, which can be fatal if not treat properly. We report a case of a 50-year-old man who presented with sudden onset of left upper quadrant pain and shock. This patient underwent splenectomy with distal pancreatectomy. His pathological diagnosis showed splenic epithelioid hemangioendothelioma.

Giant Splenic Aneurysm with Arteriovenous (A-V) Shunt, Portal Hypertension, and Ascites

Patient: Male, 43

Final Diagnosis: Splenic aneurysm

Symptoms: Ascites • fever • portal hypertension

Medication: —

Clinical Procedure: —

Specialty: Surgery

Spleen-Preserving Surgery in Splenic Artery Aneurysm

Endovascular interventions are increasingly used in the treatment of a splenic artery aneurysm (SAA), which is a rare and life-threatening clinical disorder. However, in cases of SAA rupture, minimally invasive interventions are unsuitable, and open surgery remains the gold standard method. In open surgery, care should be taken to preserve the spleen and its immune function in cases where an arterial segment of sufficient length allows for reconstruction. An SAA was detected in a 51-year-old woman who presented to our polyclinic with left upper quadrant pain. An endovascular intervention was unsuccessful, and open surgery was performed. Approximately 5 cm of aneurysm in the middle segment of the splenic artery was treated by arterial anastomosis, and the spleen was preserved. The patient experienced no postoperative complications and remained asymptomatic at the seventh month of follow-up. The aim of this case report is to emphasize the importance of splenic sparing surgery in cases of SAAs.