The prevalence and morphometry of an accessory spleen: A meta-analysis and systematic review of 22,487 patients

Rupture of an accessory spleen caused by blunt trauma

PURPOSE

The accessory spleen is quite a common abdominal anomaly. However, the traumatic accessory spleen rupture is an extremely rare condition requiring surgical intervention, even laparotomy. 9 cases of traumatic accessory spleen were found published between 1962 and 2022. The study aims to evaluate traumatic accessory spleen rupture cases regarding their causes, clinical course, and possible diagnosis without surgery and treatment.

METHODS

Desk research method using available online databases. Descriptive methods were employed to analyze the collected data. The results are summarized in the Table concerning gender, age, injury details, accessory spleen injury characteristics, treatment, and others such as previous splenectomy or primary spleen involvement in injury or accompanying abdominal injuries.

RESULTS

In total, there were 9 cases of traumatic accessory spleen, of which 2 were managed conservatively and the remaining 7 were treated operatively. All the patients survived. One-third of all included patients already had their primary spleen removed, which facilitated the diagnosis of traumatic rupture of an accessory spleen. The proper diagnosis of an accessory spleen rupture was concluded in 2 cases and confirmed in surgery.

CONCLUSION

The recognition of the traumatic rupture of an accessory spleen before surgery is challenging but can be made easier if the patient underwent splenectomy before. The traumatic accessory spleen rupture does not coexist with an injury of a primary spleen.

Are accessory spleen screening and resection in refractory immune cytopenia an effective strategy or a waste of resources?

Splenectomy remains an effective treatment for refractory immune cytopenia (RIC), which encompasses immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA). Accessory spleens (AS) have been described without identifying specific risk factors. We retrospectively analyzed patients with RIC after splenectomy who underwent splenic scintigraphy (SS) at our institution. Seventy-one patients were included. Sixty-two patients had ITP, five had AIHA, and four had Evans syndrome. Seventy-five percent (n = 53) were women. Eleven patients (15.5%) had an AS detected by SS. A complete response (CR) to first-line steroids (odds ratio (OR) 5.75, 95% confidence interval (CI) 1.37-24.14, p = 0.017) and the absence of Howell-Jolly bodies (HJB) in peripheral blood smear (PBS) (OR 11.37, 95% CI 2.70-47.85, p = 0.001) were found to be risk factors. Patients with both elements had a higher rate of AS (83.3%) when compared to those with one or no factors (p < 0.001). Eight patients (73%) underwent an accessory splenectomy: seven (87.5%) achieved a CR, and none had perioperative complications. The presence of HJB in PBS changed from 25 to 87.5% after accessory splenectomy. We recommend the search for an AS via SS in patients with RIC due to ITP, who had a CR to corticosteroids and the absence of HJB in PBS. Accessory splenectomy is a safe and effective procedure.

Accessory Spleen Mimicking an Intrahepatic Neoplasm: A Rare Case Report

Accessory spleen and splenosis are two types of ectopic spleen. An accessory spleen can be found in various sites in the abdomen, but an intrahepatic accessory spleen is very rare though many case reports of intrahepatic splenosis are available. This case report presents the incidental diagnosis of accessory spleen in the liver of a 57-year-old male while undergoing laparoscopic diaphragmatic repair. The patient had a history of splenectomy 27 years ago for hereditary spherocytosis, but his routine haemogram did not show any features of the ectopic splenic function. Intraoperatively, a mass was suspected in the liver and was resected. Histopathology revealed an accessory spleen with well-preserved red and white pulp architecture. Though a history of splenectomy suggested a diagnosis of splenosis, a well-encapsulated and preserved splenic architecture confirmed the diagnosis of accessory spleen. Accessory spleen or splenosis can be diagnosed radiologically using Tc-99m-labeled heat-denatured red blood cells (HRBC) and Tc-99m sulfur colloid scans, but the gold standard is histopathological examination. Ectopic spleen is mostly asymptomatic but usually results in unnecessary surgeries as it is difficult to differentiate from benign or malignant tumors. Thus, a high degree of suspicion and awareness is necessary for early and prompt diagnosis.

Radiologic Findings of Single Accessory Splenic Infarction in a Patient with Accessory Spleens in the Abdominal Cavity: A Case Report

The presence of multiple accessory spleens in the abdominal cavity is typically limited to two, with cases involving a higher number being exceedingly rare. Concurrently, accessory spleen infarction is remarkably uncommon, primarily resulting from torsion of the vascular pedicle. In this report, we present a case of a 19-year-old male who experienced infarction in one of four accessory spleens. Imaging diagnosis proved challenging, with the definitive diagnosis being made through postoperative pathology, revealing no torsion in the affected accessory spleen. Following surgery combined with anti-inflammatory and analgesic treatment, the patient exhibited an uneventful recovery. No complications were observed at the 3-month follow-up. This case indicates the challenge and difficulty of diagnosing accessory splenic infarction without torsion in imaging diagnosis. Employing a multimodality approach and diffusion-weighted imaging may aid in confirming the diagnosis.

Accessory spleens recapitulate the immune microenvironment of the main spleen in immune thrombocytopenia

Accessory spleens (AcS) may play a relevant role in immune thrombocytopenia (ITP) and possibly contribute to ITP relapse following splenectomy. Little is known about the immune microenvironment of AcS in ITP. To address this issue, we compared the histological features of eight matched AcS and main spleen (MS) samples, obtained from adult patients with primary ITP. AcS and MS had overlapping immune architectural features and lymphoid composition, suggesting that similar immunologic events occur in AcS and MS of ITP. These findings may have implications for the potential mechanisms of AcS-mediated ITP relapse. Further studies are needed to confirm these results and to dissect spleen immunity in ITP.

Laparoscopic treatment for an intrapancreatic accessory spleen: A case report

Malignant pancreatic tumors have early metastasis, aggressive behavior and poor prognosis. Surgeons often need to judge whether a patient needs prompt surgery when a pancreatic lesion is found. The accessory spleen is a congenital developmental malformation rather than a tumor and does not require surgical resection. Here, we report a 47-year-old man who underwent routine gastroscopic examination, and a submucosal eminence of the duodenal bulb was detected. The patient was asymptomatic and laboratory tests were unremarkable. Duodenal neuroendocrine neoplasm (G2) was considered following endoscopic submucosal dissection (ESD). Further examination showed a lesion in the tail of the pancreas and multiple accessory spleens. The lesion in the tail of the pancreas was Ga-68 positive and was highly considered a pancreatic neuroendocrine tumor (pNET). Based on this clinical evidence, laparoscopic spleen-preserving distal pancreatectomy (Kimura) was performed. However, the results of the postoperative pathological diagnosis indicated an intrapancreatic accessory spleen (IPAS). Given the findings of this case, we should explore more accurate diagnostic methods for IPAS to avoid unnecessary surgery.

Accessory Spleen Masquerading as an Intrapancreatic Tumor: A Case Report

The finding of splenic tissue within the pancreas, also known as splenosis or intrapancreatic accessory spleen (IPAS), is a relatively uncommon condition that presents as an intrapancreatic mass. The discovery of an intrapancreatic mass often prompts a thorough diagnostic workup for a primary pancreatic malignancy, often exposing patients to unnecessary risks associated with invasive testing and even surgery. The benign, asymptomatic nature of this finding places emphasis on utilizing non-invasive techniques for confirmation of the diagnosis, reducing risks of morbidity and mortality in this patient population. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) will display near-identical signal intensities (SI) between the spleen and the intrapancreatic mass, as well as identical contrast-enhancement patterns. Nuclear medicine evaluation with Tc-99m heat-damaged red blood cells (HDRBCs) is often used as a confirmatory test and allows for differentiation from malignancies.

Guidelines for the performance of minimally invasive splenectomy

BACKGROUND

Minimally invasive splenectomy (MIS) is increasingly favored for the treatment of benign and malignant diseases of the spleen over open access approaches. While many studies cite the superiority of MIS in terms of decreased morbidity and length of stay over a traditional open approach, the comparative effectiveness of specific technical and peri-operative approaches to MIS is unclear.

OBJECTIVE

To develop evidence-based guidelines that support clinicians, patients, and others in decisions on the peri-operative performance of MIS.

METHODS

A guidelines committee panel of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) including methodologists used the Grading of Recommendations Assessment, Development and Evaluation approach to grade the certainty of evidence and formulate recommendations.

RESULTS

Informed by a systematic review of the evidence, the panel agreed on eight recommendations for the peri-operative performance of MIS for adults and children in elective situations addressing six key questions.

CONCLUSIONS

Conditional recommendations were made in favor of lateral positioning for non-hematologic disease, intra-operative platelet administration for patients with idiopathic thrombocytopenic purpura instead of preoperative administration, and the use of mechanical devices to control the splenic hilum. Further, a conditional recommendation was made against routine intra-operative drain placement.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.

Ferumoxytol-enhanced MR imaging for differentiating intrapancreatic splenules from other tumors

Objectives

Ferumoxytol is an ultra-small superparamagnetic iron oxide (USPIO) agent that is taken up by splenic tissue. This study describes our initial institutional experience of ferumoxytol-enhanced MRI (feMRI) for differentiating intrapancreatic splenules (IPS) from other pancreatic lesions.

Methods

In this retrospective study, patients with computed tomographic imaging that identified small enhancing lesions in the tail of the pancreas subsequently underwent feMRI for further characterization. The feMRI protocol included T2-weighted (T2w) imaging with and without fat suppression (FS), R2* mapping, diffusion-weighted imaging (DWI), and T1-weighted (T1w) imaging with FS, prior to contrast injection. Immediately after slow intravenous infusion with 3 mg/kg body weight ferumoxytol, T1w was repeated. Delayed imaging with all sequences were obtained 24–72 h after ferumoxytol administration.

Results

Seven patients underwent feMRI. In two patients, the pancreatic lesions were presumed as pancreatic neuroendocrine tumor (PNET) from feMRI and in the remaining 5 IPS. One of the two patients with PNET was symptomatic for NET. In another symptomatic patient with pathologically proven duodenal NET and suspected PNET, the pancreatic lesion was proven to be an IPS on feMRI. IPS demonstrated strong negative enhancement in feMRI on T2w and increased R2* values consistent with splenic tissue, while the presumed PNETs did not enhance. T2w FS was helpful on the pre-contrast images to identify IPS, while R2* did on post-contrast images. Neither DWI nor T1w contributed to differentiating PNETs from IPS.

Conclusions

This study demonstrates the potential utility of feMRI as a helpful adjunct diagnostic tool for differentiating IPS from other pancreatic lesions. Further studies in larger patient cohorts are needed.

Heterotopic accessory spleen with squamous epithelial cyst in pancreas mimicking other pancreatic tumor: a case report

A 49-year-old female undergoing a periodic health examination at other hospital revealed a mass in the tail of pancreas. The patient denied any personal history of surgery except subtotal hysterectomy because of multiple myomas in uterus 7 years ago, family history of abdominal cancer and trauma. Physical examination and laboratory finding (including tumor marker) were unremarkable. Chest X-ray result was normal. Contrast enhanced ultrasound (CEUS) examination showed a well-defined hypoechoic pancreatic mass which was suggestive of solid pseudopapillary tumor. Contrast enhanced computed tomography (CE-CT) of the abdomen revealed a mass of hypodensity suggestive of intraductal papillary mucinous neoplasm. Because of the risk of bleeding and exclusion of surgical contraindications, patient underwent laparoscopic surgery. Intraoperatively, a solid mass was identified in the tail of pancreas, the intraoperative frozen pathological examination suggested a heterotopic accessary spleen (HAS) with squamous epithelial cyst. Partial pancreatectomy was performed. The uniqueness of this case is that the spleen can be ectopic to the pancreas, what is even more unexpected is that the HAS undergone cystic change. When encountering a pancreatic mass, we need to think about the possibility of HAS. In conclusion, it is important to diagnose HAS with squamous cyst in the pancreatic tail presenting as other pancreatic masses.

Post-splenectomy sepsis: preventative strategies, challenges, and solutions

Removal of the spleen had already been established as a routine technique to treat splenic trauma and other diseases affecting the spleen before the anatomy, physiology, and function of the spleen were known in the mid-twentieth century. It is now widely accepted that the splenectomized individual is at increased risk for infection, in particular, overwhelming post-splenectomy infection (OPSI). OPSI is a syndrome of fulminant sepsis occurring in splenectomized (asplenic) or hyposplenic individuals that is associated with high mortality and morbidity. Poorly opsonized bacteria such as encapsulated bacteria, in particular, Streptococcus pneumoniae, are often implicated in sepsis. The spleen is a reticuloendothelial organ that facilitates opsonization and phagocytosis of pathogens, in addition to cellular maintenance. Splenectomy is associated with an impairment in immunoglobulin production, antibody-mediated clearance, and phagocytosis, leading to an increased risk of infection and sepsis. Early identification of the at-risk patient, early blood cultures prior to antibiotic administration, urgent blood smears and fast pathogen-detection tests, and sepsis bundles should be utilized in these patients. Prompt management and aggressive treatment can alter the course of disease in the at-risk splenectomized patient. Overwhelming post-splenectomy infection can be prevented through vaccination, chemoprophylaxis, and patient education. This article evaluates post-splenectomy sepsis by summarizing the anatomy and function of the spleen, physiological changes after splenectomy that predispose the splenectomized patient to infection, and current management and prevention strategies.

Heat-Damaged Red Blood Cell Scintigraphy in Helping Interpretation of 68Ga-DOTATATE PET/CT

Ga-DOTATATE PET/CT was performed to determine the cause of endogenous Cushing syndrome in a 10-year-old boy whose MRI studies did not reveal pituitary or adrenal gland abnormality. The PET/CT images demonstrated an intense activity in a small soft tissue nodule in the left upper abdomen where splenules are commonly located. Heat-damaged Tc-labeled red blood cell imaging showed that this soft tissue nodule did not have increased red blood cell activity, which indicated that this lesion was a true somatostatin receptor-rich lesion. The pathology result following surgical resection of the lesion confirmed adrenocorticotropic hormone-producing neuroendocrine tumor.

Recognizing intrapancreatic accessory spleen via EUS: Interobserver variability

Background and Objective:

Accessory spleen (AS) may be encountered as an intrapancreatic lesion on EUS. This can look similar to other pancreatic pathologies and may lead to unnecessary interventions. The goal of this study was to evaluate the accuracy of EUS in distinguishing intrapancreatic AS (IPAS) from other pancreatic lesions.

Materials and Methods:

Twelve sets of endoscopic images of the spleen and various pancreatic lesions confirmed on histology or cytology were gathered. Ten endosonographers were asked to characterize and identify the lesions. The responses were analyzed via Excel and the interobserver agreement was analyzed using Gwet's agreement coefficient statistic via Stata I/C v15.

Results:

In our sample, the interobserver agreement was 0.37 (−1–1; 0–0.2 poor, 0.2–0.4 fair, 0.4–0.6 moderate, 0.6–0.8 substantial, and 0.8–1.0 almost perfect) for determining whether or not the pancreatic lesion is IPAS. The reviewers were able to correctly determine IPAS endosonographically with a sensitivity of 77%, specificity of 74%, and positive and negative predictive values of 50% and 92%, respectively.

Conclusion:

There is a moderate-to-substantial interobserver agreement in describing the sonographic characteristics of the pancreatic lesions, such as the shape, echogenicity compared to spleen, echotexture, and border of the lesions. However, the interobserver agreement is only fair when deciding if the pancreatic lesion is an IPAS. The similar profile of IPAS and pancreatic neuroendocrine tumor could confound the diagnosis of IPAS, thus contributing to the decreased interobserver agreement. This study demonstrates that EUS criteria alone are not accurate for IPAS diagnosis. Fine-needle aspiration (FNA) may be required for a confirmatory diagnosis.

Incomplete penetrance for isolated congenital asplenia in humans with mutations in translated and untranslated RPSA exons

Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.