Splenic hemangiomas and hamartomas: MR imaging characteristics of 28 lesions

Diagnostic approach to splenic lesions

BACKGROUND

 Splenic lesions are rare and mostly incidental findings on cross-sectional imaging. Most lesions are of benign nature and can be correctly identified based on imaging characteristics. Further, invasive evaluation is only necessary in cases of splenic lesions with uncertain or potentially malignant etiology.

METHOD

 While in most cases a correct diagnosis can be made from computed tomography (CT), (additional) magnetic resonance imaging (MRI) can aid in the identification of lesions. As these lesions are rare, only a few of the differential diagnoses are regularly diagnosed in the clinical routine.

RESULT AND CONCLUSION

 This review presents the differential diagnoses of splenic lesions, including imaging characteristics and a flowchart to determine the right diagnosis. In conjunction with laboratory results and clinical symptoms, histological workup is necessary only in a few cases, especially in incidental findings. In these cases, image-guided biopsies should be preferred over splenectomy, if possible.

KEY POINTS

  · Splenic lesions are rare and are usually incidental findings on abdominal imaging. · CT imaging and MRI imaging are the diagnostic tools of choice for the further workup of splenic lesions. · Based on their image morphological characteristics, a large number of splenic lesions can be assigned to one entity and do not need histological analysis.

CITATION FORMAT

· Krähling H, Seidensticker M, Heindel WL et al. Diagnostic approach to splenic lesions. Fortschr Röntgenstr 2024; 196: 573 - 581.

Benign splenic lesions in BAP1-tumor predisposition syndrome: a case series

BAP1-Tumor Predisposition Syndrome (TPDS) is caused by germline variants in BAP1 and predisposes to solid tumors. After observation of a radiologically malignant-appearing splenic mass with benign pathology in a patient with BAP1-TPDS, we sought to retrospectively characterize splenic lesions in individuals with BAP1-TPDS seen at a comprehensive cancer center. A dedicated radiology review for splenic abnormalities was performed. We identified 37 individuals with BAP1-TPDS, 81% with a history of cancer. Of 33 individuals with abdominal imaging, 10 (30%) had splenic lesions, and none were shown to be malignant on follow-up. Splenectomy in an individual with suspected splenic angiosarcoma showed a benign vascular neoplasm with loss of nuclear staining for BAP1 in a subset of cells. Benign splenic lesions appear to be common and potentially BAP1-driven in individuals with BAP1-TPDS; confirmation of these findings could lead to more conservative management and avoidance of splenectomy.

Splenic hamartomas in children

Splenic hamartomas (SHs) are uncommon, benign vascular lesions of unclear etiology and are mostly found incidentally on abdominal images, at surgery, or at autopsy. Since the first case description, in 1861, less than 50 pediatric SH cases have been reported in the literature. In this article, we have performed an analysis of all SH cases in children published in the literature to date and presented our case of an 8-year-old male with SH. These lesions in children were shown to cause symptoms more often than in the adult population. The observed SH sizes in children ranged from a few millimeters to 18 cm, and the symptomatic lesions were mostly larger or multiple. The most common clinical finding was splenomegaly. Signs of hypersplenism were present in children with a single SH larger than 4.5 cm (diameter range: 4.5-18.0 cm) and in those with multiple hamartomas, ranging from a few millimeters to 5 cm. Eighty percent of patients with available laboratory findings had hematological abnormalities such as anemia, thrombocytopenia, or pancytopenia. Other symptoms and signs included abdominal pain, recurrent infections, fever, night sweats, lethargy, growth retardation, and weight loss. The use of multiple imaging modalities may suggest the preoperative diagnosis of a splenic mass in children and determine the therapeutic approach. However, the final diagnosis of SH relies on histopathological evaluation. Surgery, including total or partial splenectomy (PS), is the mainstay of SH management. Although total splenectomy carries a greater risk of overwhelming post-splenectomy infection than PS it has remained the most performed surgical procedure in children with SH. In the majority of pediatric patients with symptomatic SH, resolution of symptoms and resolution or improvement of cytopenias occurred after surgical treatment.

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.

Algorithmic Approach to the Splenic Lesion Based on Radiologic-Pathologic Correlation

Splenic lesions are commonly discovered incidentally at imaging, without clinical signs or symptoms that may aid in diagnosis. As such, the differential diagnosis and subsequent management are based primarily on imaging characteristics. Much has been written about the myriad pathologic conditions that can occur in the spleen; however, there is little guidance on the approach to an incidental splenic mass. Applying an approach frequently used in imaging to the splenic mass-based on the number and consistency of lesions and refined by supplementary imaging features-allows formulation of a useful differential diagnosis. Solitary cystic masses include true cysts, pseudocysts, and parasitic cysts. When multiple cystic lesions are present, the differential diagnosis expands to include infectious lesions (abscess or microabscesses) and lymphangioma (a benign cystic neoplasm). Hemangioma is the most common solitary solid mass, although other vascular lesions (hamartoma, sclerosing angiomatoid nodular transformation) and nonvascular lesions (inflammatory pseudotumor, lymphoma) manifest as solitary and solid. When multiple solid masses are present, diffuse inflammatory disease (sarcoidosis), littoral cell angioma, and lymphoma should be considered. Malignancies, such as angiosarcoma or metastasis, can manifest as solitary or multiple and solid or cystic masses but are typically associated with symptoms or widespread primary malignancy. Careful assessment of the multimodality imaging characteristics of splenic lesions based on this approach aids the radiologist faced with the incidental splenic lesion. Online supplemental material is available for this article. Work of the U.S. Government published under an exclusive license with the RSNA.

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.

Incidental Splenic Findings on Cross-Sectional Imaging

Incidental splenic focal findings are commonly encountered in clinical practice and frequently represent a diagnostic dilemma due to nonspecific imaging features. Most are benign, particularly in patients without a history of malignancy and without symptoms of fever, weight loss, or left upper quadrant or epigastric pain. Incidental malignant splenic processes are exceedingly rare. This article reviews imaging characteristics of incidental focal splenic findings, and proposes a practical approach for management of such findings, which can prevent unnecessary workup and its related drawbacks in clinical practice.

Focal splenic lesions: Imaging spectrum of diseases on CT, MRI and PET/CT

The spleen can be affected by a variety of diseases. Some of them are readily identified as variations of normal or benign diseases on imaging. However, for a substantial number of focal splenic abnormalities, the diagnosis can be difficult so that histopathologic analysis may be required for a definite diagnosis. In this review, the typical splenic abnormalities that can be diagnosed with imaging with a high degree of confidence are illustrated. The complementary role of computed tomography (CT), magnetic resonance imaging and positron emission tomography/CT that helps make a diagnostic approach is discussed. Finally, current applications and future trends of radiomics and artificial intelligence for the diagnosis of splenic diseases are addressed.

Revisiting the Spleen—An Imaging Review of the Common and Uncommon Splenic Pathology

The spleen is the largest lymphatic organ and is responsible for both hematological and immunological functions. Several common etiologies such as trauma, developmental variants, infectious/inflammatory conditions, and benign and malignant lesions can occur in the spleen. The role of imaging modalities such as ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) in diagnosing these conditions continues to evolve. The main objective of this review article is to illustrate the role of imaging in identifying the common and uncommon pathology of the spleen.

Iron-containing pathologies of the spleen: magnetic resonance imaging features with pathologic correlation

Systemic and non-systemic pathologies that involve iron deposition within the spleen have characteristic features on MRI due to the susceptibility properties of deposited iron, or hemosiderin. These lesions will have signal loss on longer echo sequences due to the T2* effect when evaluated with dual-echo gradient-echo sequences. The pathophysiology of systemic and localized iron sequestration disease processes can elucidate an underlying diagnosis based on these imaging features in conjunction with clinical information.

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

PURPOSE

This study aimed to investigate the role of cross-sectional imaging in differentiating between benign and malignant splenic lesions based on various imaging features.

METHODS

Database of imaging reports from January 2015 to December 2017 were searched dedicatedly for "spleen" or "splenic" terms to identify patients with splenic lesions found either on CT or MRI. The study cohort consisted of patients who had available histological reports or had follow-up imaging for a minimum of one year. Patients were categorized into the benign subcohort if they did not have a history of extra-splenic malignancy, and had a splenic lesion(s) falling into one of these categories: benign histopathology on biopsy, stable size and enhancement, or decreased size on follow-up imaging. Those who had malignant histopathology on biopsy were included in the malignant subcohort. Various morphologic features and enhancement patterns of these lesions were carefully reviewed by two radiologists who were blinded to the final histopathologic diagnosis.

RESULTS

We identified 161 patients (54 % males, mean age ± SD = 59.7 ± 15.4) including 124 (77 %) in the benign and 37 (23 %) in the malignant subcohort. Benign lesions were more likely to be cystic (21.7 % vs 2.7 %, p < 0.001), homogenous (59.7 % vs. 29.7 %, p = 0.001) and to demonstrate well-defined borders (69.3 % vs. 29.7 % p= <0.001). Malignant lesions had significantly larger diameter (median size: 15 vs 11 mm, p = 0.03). Restricted diffusion was not seen in any of the benign lesions; however, 50 % of malignant lesions demonstrated restricted diffusion (p = 0.003). Features such as lesion distribution, presence of calcification, splenomegaly and number of lesions were not significantly different between benign and malignant lesions.

CONCLUSION

Smaller lesion diameter, well-defined border and homogeneity favor benign nature of splenic lesions while restricted diffusion should raise suspicion for malignancy.

Giant epidermoid cyst of the spleen in a pediatric patient: A case report

RATIONALE

Splenic cysts (SCs) are rare findings in children, particularly the youngest. Here, we discuss a case that is useful for the differential diagnosis and treatment of SCs.

PATIENT CONCERNS

A 9-year-old Albanian boy was admitted for severe abdominal pain localized mainly in the left hypochondrium for approximately 24 hours. His medical history was without significant clinical problems.

DIAGNOSIS

Splenomegaly was diagnosed during the first clinical examination, and laboratory tests showed an increase in CA 125 and CA19-9. Abdominal ultrasonography showed splenomegaly with a large hypoechoic oval formation with well-defined margins and the presence of internal fine suspension spots; abdominal magnetic resonance imaging revealed a well-defined SC. The cystic lesion caused major effects on the neighboring organs, shifting them from their normal sites.

INTERVENTIONS

Considering the mass's volume, an open splenectomy was performed. Upon histopathological examination, the lesion was characterized by a stratified squamous keratinized thick lining and brownish liquid contents consisting of lymphocytes, erythrocytes, and hemosiderin-rich macrophages. These features informed the diagnosis of a giant epidermoid SC.

OUTCOMES

No complications occurred in the post-operative period, and blood exams revealed the quick normalization of CA 19.9 and CA 125 levels. The boy was discharged on the eighth post-operative day. No complaints were documented during the regular follow-up.

LESSONS

This case shows that modern imaging techniques are useful for the differential diagnosis between epithelial mass and SCs of different origins. Open splenectomy has been the treatment of choice for years, but future studies should clarify whether more conservative methods are associated with positive long-term outcomes and if they can also be used for large SCs.

Splenic Hemangioma as a Potential Pitfall on PSMA-Targeted 18F-DCFPyL PET/CT

A 69-year-old man with biochemical recurrence after radical prostatectomy underwent 6 months of androgen deprivation therapy. Upon discontinuation of androgen deprivation therapy, serum prostate-specific antigen rose again to 0.69 ng/mL, and F-DCFPyL PET/CT was performed to identify the site of recurrence. However, only an intense focus of uptake in the spleen could be found. Subsequent contrast-enhanced MRI findings were pathognomonic for splenic hemangioma.

Thoracoabdominal imaging of tuberous sclerosis

Imaging of tuberous sclerosis complex has rapidly evolved over the last decade in association with increased understanding of the disease process and new treatment modalities. Tuberous sclerosis complex is best known for the neurological symptoms and the associated neuroimaging findings, and children with tuberous sclerosis complex require active surveillance of associated abnormalities in the chest, abdomen and pelvis. Common findings that require regular imaging surveillance are angiomyolipomas in the kidneys and lymphangioleiomyomatosis in the chest. However multiple rarer associations have been attributed to tuberous sclerosis complex and should be considered by radiologists reviewing any imaging in these children. In this review the authors discuss the spectrum of imaging findings in people with tuberous sclerosis complex, focusing on MR imaging findings in the chest, abdomen and pelvis.

The Incidental Splenic Mass at CT: Does It Need Further Work-up? An Observational Study

Purpose To evaluate whether an incidentally noted splenic mass at abdominal computed tomography (CT) requires further imaging work-up. Materials and Methods In this institutional review board-approved HIPAA-compliant retrospective study, a search of a CT database was performed for patients with splenic masses at CT examinations of the abdomen and chest from 2002 to 2008. Patients were divided into three groups: group 1, patients with a history of malignancy; group 2, patients with symptoms such as weight loss, fever, or pain related to the left upper quadrant and epigastrium; and group 3, patients with incidental findings. Patients' CT scans, follow-up examinations, and electronic medical records were reviewed. Final diagnoses of the causes of the masses were confirmed with imaging follow-up (83.9%), clinical follow-up (13.7%), and pathologic examination (2.4%). Results This study included 379 patients, 214 (56.5%) women and 165 (43.5%) men, with a mean age ± standard deviation of 59.3 years ± 15.3 (range, 21-97 years). There were 145 (38.3%) patients in the malignancy group, 29 (7.6%) patients in the symptomatic group, and 205 (54.1%) patients in the incidental group. The incidence of malignant splenic masses was 49 of 145 (33.8%) in the malignancy group, eight of 29 (27.6%) in the symptomatic group, and two of 205 (1.0%) in the incidental group (P < .0001). The incidental group consisted of new diagnoses of lymphoma in one (50%) patient and metastases from ovarian carcinoma in one (50%) patient. Malignant splenic masses in the incidental group were not indeterminate, because synchronous tumors in other organs were diagnostic of malignancy. Conclusion In an incidental splenic mass, the likelihood of malignancy is very low (1.0%). Therefore, follow-up of incidental splenic masses may not be indicated. ^© RSNA, 2018.

Spontaneous splenic artery rupture in a patient with an unclassified malignant spindle cell tumor of the spleen: report of a case

The purpose of this paper was to describe an unusual manifestation of a sarcoma of the spleen and to raise awareness for spontaneous rupture of the splenic vessels in patients with splenic tumors. A 70-year-old man was admitted to our institution, suffering from left upper quadrant abdominal pain. Upon physical examination, a large and tender abdominal mass was palpated. Abdominal computed tomography showed a heterogenous enlarged spleen with active contrast extravasation from the splenic artery, free intraperitoneal fluid, and a retroperitoneal hematoma. The patient was treated with angioembolization of the splenic artery. Because of rebleeding, splenectomy was performed. Pathology revealed the spleen to be involved with an unclassified malignant spindle cell neoplasm. We concluded that in the case of spontaneous rupture of the splenic artery, accompanied with a radiologic appearance of an enlarged spleen, the diagnosis of sarcoma should be included in the differential diagnosis.

Asymptomatic multinodular splenoma (splenic hamartoma) in a child with sickle cell anemia

Splenoma is a rare and benign malformation usually fortuitously diagnosed during imaging, surgery or, unfortunately, at autopsy. Although splenoma was first described in 1861, its association with hematological pathology is a very unusual condition in children. We report the case of an asymptomatic splenoma in an 8-year-old boy with sickle cell anemia, whose diagnosis was confirmed after conventional splenectomy.

Beyond hepatic hemangiomas: the diverse appearances of gastrointestinal and genitourinary hemangiomas

Hemangiomas are common lesions, best known for their appearance in the liver. Their appearance in less common locations, such as the gastrointestinal and genitourinary tracts, is less well known. We will review the typical and atypical appearance of hemangiomas in these locations on sonography, CT, and MRI.

The value of contrast-enhanced dynamic and diffusion-weighted MR imaging for distinguishing benign and malignant splenic masses

OBJECTIVE

To assess the value of contrast-enhanced dynamic and diffusion-weighted (DW) MR imaging for differentiating malignant from benign splenic lesions.

METHODS

This retrospective study included 51 patients with 35 benign and 16 malignant focal splenic lesions. All patients underwent contrast-enhanced dynamic and DW MR imaging. Two radiologists evaluated the MR images in consensus. Significant imaging findings on univariate and multivariate analyses were identified and their diagnostic performance for predicting the malignant splenic lesion was analyzed. Using receiver-operating characteristic analysis, the optimal cut-off of the apparent diffusion coefficient (ADC) value corresponding to the maximal Youden's index (J) for differentiating the two groups was determined.

RESULTS

In univariate analysis, low signal intensity (SI) on the arterial, portal and 3-min delayed-phase images, high or iso SI on the DW image, iso or low SI on the ADC map, the presence of diffusion restriction and arterial hypovascularity with a progressive enhancement pattern were more frequently observed (p < 0.05) in malignant splenic lesions. The ADC value was significantly lower for malignancy than for benignancy (0.78 ± 0.24 vs 1.16 ± 0.53 × 10(-3) mm(2) s(-1); p < 0.001). The optimal cut-off ADC value for differentiating the two groups was 0.995 × 10(-3) mm(2) s(-1). In multivariate analysis, findings that differentiated malignant from benign splenic lesions were low SI on the 3-min delayed-phase image [odds ratio (OR), 27.68; p = 0.006] and the presence of diffusion restriction (OR, 48.01; p = 0.002). When two of these criteria were combined, 12 (75.0%) of 16 malignant splenic masses were identified with a specificity of 100%.

CONCLUSION

Contrast-enhanced dynamic and DW MR imaging may be helpful for differentiating malignant from benign splenic lesions. A low SI on the 3-min delayed phase and diffusion restriction are the most reliable findings for the differentiation of malignant from benign splenic lesions.

ADVANCES IN KNOWLEDGE

Dynamic and DW MR imaging help in distinguishing malignant from benign splenic lesions. A low SI on the 3-min delayed phase and diffusion restriction are the most reliable findings for the differentiation of malignant from benign splenic lesions.

A recurrent epidermoid cyst of the spleen: report of a case and literature review

BACKGROUND

Splenic cysts are rare disease. Epidermoid cysts of the spleen belong to the primary nonparasitic splenic cysts group. They are an unusual event in surgical practice. Usually, epidermoid cysts occur in children and young female. Most often, they are asymptomatic, but they may present with abdominal discomfort.

CASE PRESENTATION

We are reporting a rare case of a 23-year-old female came to our attention with history of intermittent pain and previously undergone two times to laparoscopic decapsulation of the cyst in others institutions. During hospitalization, serum and intracystic levels of tumor marker CA19-9 increased. Enhanced CT of the abdomen showed recurrent large cyst in the upper pole of the spleen with satellite nodules. Laparotomic total splenectomy was performed. Histopathological and immunoreactive examinations were executed, and they revealed stratified squamous epithelium on the inner surface of cystic wall, which was positive for EMA, CEA, and CA19-9. The diagnosis of epidermoid cyst was confirmed.

CONCLUSIONS

Recently, the surgical approach is changing towards conservative treatments in order to save the spleen in young patients for immunological reasons. Sometimes, this target is not achievable. In such circumstances, like recurrent large cyst, anomalous anatomical relationship to the surrounding tissues, total splenectomy is safe and necessary.

[Splenic hamartoma, severe thrombocytopenia, and macrocrania in a neonate: A case study]

We report a case of splenic hamartoma associated with neonatal macrocrania diagnosed in a newborn. The diagnosis was made in the first 2 days of life upon the existence of an abdominal mass in the newborn infant. Abdominal ultrasound and abdominal computed tomography supported the diagnosis, but the histological study was inconclusive. The indication for surgery is still controversial. Through a literature review, the clinical, histological, and radiological aspects are discussed. The combination of neonatal hamartoma, thrombocytopenia, and macrocrania has never been reported.

Contrast-enhanced sonography with Sonazoid as a new diagnostic tool for splenic hamartoma: a single case report

Detection of reticuloendothelial system (RES) cells is essential for the differential diagnosis of splenic hamartoma. Among the imaging techniques using contrast agents phagocytosed by RES cells, contrast-enhanced ultrasonography (CEUS) with Sonazoid is less invasive and less costly than (99m)Tc-labeled colloid scintigraphy. We report a case of non-symptomatic splenic hamartoma in a 40-year-old woman detected as an abdominal tumor by screening ultrasonography. The tumor was 4 cm in diameter, round, slightly hypoechoic, and associated with a cystic lesion. The tumor region was stained on enhanced computed tomography with prolonged enhancement, while the cystic lesion was not. The mass appeared as mainly isointense with partial hyperintensity on T1-weighted and as a mixed hypo- and hyperintense region on T2-weighted magnetic resonance images. (99m)Tc-labeled colloid scintigraphy demonstrated uptake in only the tumor region. CEUS with Sonazoid revealed that the tumor was mainly hypervascular with non-enhanced areas in the early vascular phase, but the hypervascular region appeared also as a hyperechoic area (indicating microbubble phagocytosis) in the post-vascular phase. Thus, CEUS with Sonazoid revealed all three cardinal features of splenic hamartoma: hypervascularity, presence of RES cells, and tissue heterogeneity. Splenectomy and histopathology confirmed the presence of a splenic hamartoma with associated hematoma. CEUS with Sonazoid is a promising new diagnostic tool for splenic hamartoma.

Enhanced CT and FDG PET/CT findings of splenic hamartoma

Splenic hamartomas are very rare benign vascular tumors. A 67-year-old man was referred after an incidental detection of a splenic lesion. Abdominal-enhanced CT showed a splenic lesion with progressive enhancement. This lesion showed intense FDG uptake with an SUVmax of 9.2. The patient underwent splenectomy. Splenic hamartoma was confirmed by pathologic evaluation. In this tumor, the disorganized splenic sinus contained a large amount of lymphocytes and plasma cells, which may contribute to the intense FDG uptake. This case indicates that splenic hamartoma should be included in the differential diagnosis of focal FDG accumulation along with tumor and nontumor conditions.

Differentiation of malignant from benign focal splenic lesions: added value of diffusion-weighted MRI

OBJECTIVE

The objective of our study was to evaluate the added value of diffusion-weighted imaging (DWI) for distinguishing between malignant and benign focal splenic lesions.

MATERIALS AND METHODS

This study included 53 patients with 11 malignant and 42 benign splenic lesions who underwent gadoxetic acid-enhanced MRI and DWI. Qualitative and quantitative analyses were conducted for splenic lesions. Two blinded observers evaluated the two image sets--that is, the conventional MR images alone versus the combined conventional MR and DW images--and scored their confidence for malignancy of splenic lesions. The Fisher exact test and Mann-Whitney U test were performed, and diagnostic performance values (ROC curve analysis) were evaluated.

RESULTS

All malignant lesions showed a progressive hypovascular enhancement pattern, whereas the hypervascular enhancement patterns were shown in only benign lesions (n = 20, 47.6%) (p < 0.05). The mean apparent diffusion coefficient (ADC) of the malignant lesions (0.73 × 10(-3) mm(2)/s) was significantly lower than that of the benign lesions (1.21 × 10(-3) mm(2)/s) (p < 0.001). The addition of DW images to conventional MR images showed a significant improvement for predicting malignant splenic lesions (area under ROC curve [Az] without DW images vs with DW images: 0.774 vs 0.983 for observer 1 and 0.742 vs 0.986 for observer 2) (p < 0.001). In addition, the diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of combined conventional MR and DW images were higher than those of conventional MR images alone.

CONCLUSION

The addition of DWI to conventional MRI improves differentiation of malignant from benign splenic lesions.

Nonneoplastic, benign, and malignant splenic diseases: cross-sectional imaging findings and rare disease entities

OBJECTIVE

Splenic lesions are commonly encountered and are often incidental in nature. Benign splenic vascular neoplasms include hemangioma, hamartoma, lymphangioma, extra-medullary hematopoiesis (EMH), and sclerosing angiomatoid nodular transformation (SANT). Uncommonly encountered entities of the spleen include focal EMH, focal myeloma, angiomyolipoma, and SANT. Primary splenic angiosarcoma is the most common malignant nonhematolymphoid malignancy of the spleen. Lymphoma, myeloma, and metastases are the other malignant entities involving the spleen. The clinical presentation, key imaging findings, and associations of benign, neoplastic, and malignant diseases that can involve the spleen will be discussed.

CONCLUSION

Radiologists can use multimodality imaging to diagnose entities involving the spleen by recognizing key imaging features and considering patient characteristics. However, biopsy may be warranted for definitive diagnosis when imaging findings are nonspecific.

Real-time contrast enhanced ultrasound imaging of focal splenic lesions

OBJECTIVE

To investigate the imaging features of focal splenic lesions (FSLs) on contrast-enhanced ultrasound (CEUS).

METHODS

Thirty two patients with FSLs proved by pathology were retrospectively analyzed. CEUS was performed using intravenous bolus injection of 2.4 ml sulfur hexafluoride-filled microbubble contrast agent and real time scanning. There were hemangioma (n=7), lymphoma (n=8), true cyst (n=3), infarction (n=4), hematolymphangioma (n=2), metastasis tumor (n=2), and one for each of the following entities extramedullary hemopoiesis, hamartoma, tuberculosis, Langerhans' cell histiocytosis, inflammatory pseudotumor and myxofibrosarcoma.

RESULTS

Among 21 benign lesions, 4 infarctions and 3 cysts presented non-enhancement throughout CEUS scanning, and the other 14 lesions displayed various enhancement levels with 6 (42.9%) hyper-enhancement, 2 (14.3%) iso-enhancement and 6 (42.9%) hypo-enhancement in arterial phase and 11 (78.6%) hypo-enhancement, 1 (7.1%) iso-enhancement and 2 (14.3%) hyper-enhancement in late phase, respectively. The enhancement pattern included 9 (64.3%) homogeneous, 4 (28.6%) heterogeneous and 1 (7.1%) rim-like enhancement. As for the malignant FSLs, all the lesions became completely or extensively hypo-enhancement during the late phase no matter their vascularity during arterial phase.

CONCLUSIONS

The CEUS features reported in this series may enrich the knowledge for CEUS characterization of FSLs.

The spleen revisited: an overview on magnetic resonance imaging

Despite being well visualized by different cross-sectional imaging techniques, the spleen is many times overlooked during the abdominal examination. The major reason is the low frequency of splenic abnormalities, the majority consisting of incidental findings. There has been a steady increase in the number of performed abdominal magnetic resonance imaging (MRI) studies; therefore, it is important to be familiar to the major MRI characteristics of disease processes involving the spleen, in order to interpret the findings correctly, reaching whenever possible the appropriate diagnosis. The spleen may be involved in several pathologic conditions like congenital diseases, trauma, inflammation, vascular disorders and hematologic disorders, benign and malignant tumors, and other disease processes that focally or diffusely affect the spleen. This paper presents a description and representative MRI images for many of these disorders.

Multi-modality imaging findings of splenic hamartoma: a report of nine cases and review of the literature

PURPOSE

To investigate the presentation of splenic hamartomas (SHs) on ultrasonography (US), CT and MRI.

METHODS

Nine patients (5 males and 4 females, mean age, 52.8 years) with pathologically proven SHs were included in this study. US, CT and MRI images were analyzed retrospectively, and imaging features were correlated with pathological findings.

RESULTS

SHs appeared solitary lesion (n = 8) and multiple lesions (n = 1) in the present study. (1) In 8 cases of solitary lesion, the lesions appeared as solid nodules or masses with well-defined margins and varying echogenicity (hyperecho = 5, hypoecho = 2, strong echo = 1) on ultrasound. The lesions showed iso-attenuation (n = 3) or slightly hypo-attenuation (n = 4) on unenhanced CT, and calcification were revealed in 3 lesions. MRI showed isointensity (n = 3) or hypointensity (n = 2) on the T1-weighted image, and heterogeneous hypointensity (n = 2), slightly hyperintensity (n = 2) and hyperintensity (n = 1) on the T2-weighted image. The enhanced patterns of SHs showed mild diffuse heterogeneous enhancement (n = 6) and prominent enhancement (n = 1) during arterial phase and above 7 lesions were demonstrated progressive enhancement at delayed phase on enhanced CT. One lesion without any enhancement was revealed in another patient. (2) One case of multiple lesions included 1 cystic lesion with irregular calcification and 7 solid lesions with progressive enhancement on CT images.

CONCLUSIONS

Combination of a variety of imaging modalities could more fully reflect the pathological characteristics and contribute to the diagnosis of SH.

Superparamagnetic iron oxide-enhanced magnetic resonance imaging in a case of spleen hamartoma

OBJECTIVE

To emphasize the contribution of superparamagnetic iron oxide (SPIO) contrast agent in the diagnosis of the splenic hamartoma.

CLINICAL PRESENTATION AND INTERVENTION

A 63-year-old female was admitted to our hospital with diffuse abdominal pain. An ultrasound examination revealed a 5 × 4 cm solid lesion in the spleen. Dynamic gadolinium-enhanced magnetic resonance imaging (MRI) of the abdominal findings was consistent with a splenic hamartoma. SPIO-enhanced MRI was then performed and it confirmed the diagnosis. The lesion showed a decrease of signal intensity on T2-weighted images.

CONCLUSION

This case showed that SPIO-enhanced MRI was useful for establishing a noninvasive diagnosis of the splenic hamartomas.

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.

Splenic hemangiomas: contrast-enhanced sonographic findings

OBJECTIVES

The purpose of this study was to illustrate the baseline appearance and enhancement patterns of splenic hemangiomas on contrast-enhanced sonography.

METHODS

Two experienced radiologists retrospectively reviewed by consensus baseline and contrast-enhanced sonographic examinations of 27 patients (14 women and 13 men; mean age, 58.7 years) with 27 splenic hemangiomas (mean size, 2 cm) confirmed by splenectomy, biopsy, computed tomography, and magnetic resonance imaging and follow-up.

RESULTS

On baseline sonography, 77.8% of the lesions showed a homogeneous echo texture that was mainly hyperechoic. Color Doppler imaging did not show any signal in 81.5% of the cases. After contrast agent injection, 59.2% of the splenic hemangiomas showed different degrees of contrast enhancement in the arterial phase followed by isoenhancement in the late parenchymal phase. Among these, 2 hemangiomas showed peripheral globular enhancement in the arterial phase, followed by progressive centripetal fill-in. In 29.6% of the cases, some degree of contrast enhancement was appreciable, but the hemangiomas remained substantially hypoechoic throughout the contrast-enhanced sonographic examinations, whereas in 11.1%, the combination of contrast enhancement in the arterial phase followed by wash-out in the late parenchymal phase was evident.

CONCLUSIONS

Isoechogenicity to spleen parenchyma in all phases is the most frequent typical enhancement pattern of splenic hemangiomas observed on contrast-enhanced sonography. Nevertheless, these lesions may show atypical contrast enhancement patterns; therefore, further assessment with cross-sectional techniques is needed.

Splenic hamartoma: a case report and clinicopathological analysis of Japanese cases

A 75-year-old man was referred to our department for the treatment of a gastric submucosal tumor-like protrusion which had gradually enlarged over 3 years. After examination with various types of imaging modalities, a splenic mass was diagnosed. Splenectomy was performed because it was difficult to determine preoperatively whether the splenic mass was benign or malignant. The postoperative pathological examination revealed a splenic hamartoma without malignancy. Despite the preoperative examination with advanced diagnostic imaging techniques and equipment, an accurate diagnosis of splenic hamartoma is difficult due to its rarity, lack of specific symptoms, and various inadequacies of radiological imaging techniques. Here we present a rare case of splenic hamartoma and discuss the clinical characteristics obtained from a review of Japanese cases of this rare condition.

Gastrointestinal tumors in children

Although tumors arising from the spleen, pancreas, and gastrointestinal tract in the pediatric population are relatively uncommon, imaging plays an important role in diagnosis, staging, and treatment planning. Initial imaging with abdominal radiograph contributes to the evaluation for intestinal obstruction, constipation, and mass effect, and sometimes may reveal areas of calcification.

Non-parasitic splenic cysts

This article gives an overview of the topic, with emphasis on current concepts and management of the clinical situations in question, in particular the concepts related to treatment. An extensive review of the etiology and monitoring of patients with non-parasitic splenic cysts is also made. These reports are derived from major clinical studies published in the current medical literature.

Primary and secondary neoplasms of the spleen

With the exception of lymphoma involving the spleen, other primary and secondary neoplasms are rare and infrequently encountered. Primary malignant neoplasms involving the spleen are lymphoma and angiosarcoma. Primary benign neoplasms involving the spleen include hemangioma, lymphangioma, littoral cell angioma and splenic cyst and solid lesions such as hamartoma and inflammatory pseudotumor.

Laparoscopic splenectomy for splenic hamartoma: Case management and clinical consequences

Splenic hamartoma is a rare benign tumor, and although minimally invasive surgery may be suitable for this condition, there have only been 2 previous reports of laparoscopic surgery. Here we report the third case of splenic hamartoma managed by laparoscopic splenectomy. A 37-year-old male was incidentally diagnosed by abdominal ultrasonography with a hypoechoic mass measuring 2.5 cm × 2.4 cm in the spleen. Color Doppler sonography showed multiple flow signals within the mass and contrast-enhanced computed tomography revealed strong enhancement of the lesion. On T1- and T2-weighted magnetic resonance images, the splenic mass was demonstrated as isointense and hyperintense respectively. Although a malignant tumor could not be ruled out, a hand-assisted laparoscopic splenectomy was performed because the splenic mass was limited in size and had not invaded adjacent organs. The pathological diagnosis was splenic hamartoma. The postoperative course was uneventful and the patient was discharged by the seventh postoperative day. Although splenic hamartomas have some specific imaging features, more reports and analyses of these cases are required to increase the reliability of the diagnosis and management. Hand-assisted laparoscopic splenectomy may play a pivotal role in the postoperative diagnosis and management of this condition.

Differentiation of benign from malignant focal splenic lesions using sulfur hexafluoride-filled microbubble contrast-enhanced pulse-inversion sonography

OBJECTIVE

The purpose of our study was to evaluate whether sonographic characterization of focal splenic lesions could be improved by using low mechanical index pulse-inversion sonography after sulfur hexafluoride-filled microbubble injection.

MATERIALS AND METHODS

One hundred forty-seven splenic lesions (68 benign, 79 malignant) in 147 patients (81 men, 66 women; mean age, 51 years) underwent baseline gray-scale sonography and sulfur hexafluoride-enhanced low-acoustic-power pulse-inversion sonography (mechanical index < 0.1). Two site investigators assessed in consensus lesion and splenic enhancement during arterial and parenchymal phases. Four readers (readers 1 and 2, blinded; and readers 3 and 4, unblinded to clinical data) independently reviewed baseline and contrast-enhanced sonograms and provided confidence rating for diagnosis of malignancy or benignancy. Accuracy, sensitivity, specificity, positive and negative predictive values, and areas under the receiver operating characteristic curves (A(z)) were calculated by considering biopsy results or splenectomy (51 patients) or CT or MR images followed by serial sonography 6-12 months apart (96 patients) as reference standards.

RESULTS

Benign lesions appeared predominately non- or isoenhancing relative to splenic parenchyma, whereas malignant lesions appeared predominately progressively hypoenhancing. For correct diagnosis of benignancy or malignancy, review of contrast-enhanced sonography after baseline sonography yielded significantly improved diagnostic performance (overall accuracy, 51%, 43%, 70%, and 74% before vs 83%, 81%, 92%, and 91% after contrast-enhanced sonography for readers 1, 2, 3, and 4; p < 0.05; respectively) and significantly improved diagnostic confidence (A(z), 0.770, 0.678, 0.900, and 0.917 before vs 0.935, 0.917, 0.984, and 0.959 after contrast-enhanced sonography for readers 1, 2, 3, and 4; p < 0.05; respectively).

CONCLUSION

Sulfur hexafluoride-filled microbubble-enhanced sonography improves characterization of focal splenic lesions with and without the availability of clinical data.

The pediatric spleen

Many pathological processes affect the spleen in children. As a basis for recognizing pathology, knowledge of the normal imaging appearance of the pediatric spleen is needed. In addition to congenital anomalies and trauma, pathology of the pediatric spleen includes enlargement (splenomegaly), cysts, neoplasms, infection and infarction. Specific diseases processes, including sickle cell anemia and Gaucher disease, may have specific affects on the spleen.

Histiocytic sarcoma of the spleen: case report of asymptomatic onset of thrombocytopenia and complex imaging features

Histiocytic sarcoma of the spleen, in which the malignant cells display morphologic and immunophenotypic features similar to those of mature tissue histiocytes, is a rare but potentially lethal condition that can remain asymptomatic or only mildly symptomatic for a long period of time. We studied a case of histiocytic sarcoma of the spleen in an 82-year-old woman with prolonged chronic thrombocytopenia that was non-responsive to steroid therapy. Ultrasonography, computed tomography, and magnetic resonance imaging showed a characteristically enlarged spleen and liver. Palliative irradiation therapy was clinically effective; however, disease progression proved lethal. Autopsy revealed the proliferation of tumor cells within the splenic sinus and the liver sinusoids, which displayed extreme hemophagocytosis and strong expression of the histiocytic markers CD68 (KP1 and PG-M1) and CD163. The postmortem diagnosis showed histiocytic sarcoma of the spleen with liver infiltration. This and previous reports indicate that early detection (facilitated by imaging and clinical features) and management may improve patient prognosis and survival. Histiocytic sarcoma of the spleen should be considered as a differential diagnosis in therapeutically unresponsive patients with chronic thrombocytopenia.

[Diagnostic imaging of splenic disease]

Primary diseases of the spleen are relatively rare. More frequently, the spleen is involved secondarily in hematological, oncological, infectious, immunological, vascular, and other systemic diseases. The spleen is the most commonly injured organ in blunt abdominal trauma. Anatomical and physiological basics are explained, in addition to embryological facts with resulting abnormalities, such as accessory and "wandering" spleen, and polysplenia. The most frequent primary and secondary diseases of the spleen, including rare diagnoses, are presented and illustrated. Hemangioma represents the most common primary benign tumor, and lymphoma the most common primary malignant tumor of the spleen. Diagnostic imaging does not a allow safe differentiation between Hodgkin's and non-Hodgkin's lymphoma. One section deals with the clinical value and diagnostic workup of incidentally detected lesions. Simple cysts and calcifications need neither clarification nor a follow-up examination. Atypical cysts should be controlled within 3-6 months. Additional clarification using CT or MRT should be reserved for cases with a strong suspicion of clinically relevant primary or secondary splenic disease.

Solitary splenic lesions

Solitary splenic lesions are unusual. A differential diagnosis can be organized around their basic imaging appearance as either predominantly cystic or solid. Other imaging characteristics, including vascular enhancement and activity on Tc-99m sulfur colloid scan, as well as clinical history may narrow the diagnostic possibilities. Cystic lesions include post-traumatic, inflammatory and infectious pseudocysts, congenital cysts, lymphangiomas and cystic metastasis. Solid lesions include both nonneoplastic lesions such as splenic hamartoma, benign tumors such as hemangioma and malignant masses including lymphoma and angiosarcoma. Percutaneous biopsy may be used for histologic diagnosis when required.