Renal sarcoidosis: approach to diagnosis and management

Kidney manifestations of sarcoidosis

Renal involvement is a clinically relevant organ manifestation of sarcoidosis, leading to increased morbidity and complications. Although the exact incidence remains unknown, renal disease is likely to occur in up to one third of all sarcoidosis patients. Every patient with newly diagnosed sarcoidosis should receive a renal work-up and screening for disrupted calcium metabolism. Amid various forms of glomerulonephritis, granulomatous interstitial nephritis is the most common one, but it rarely leads to renal impairment. Histologically, granulomas can be absent. Nephrocalcinosis and nephrolithiasis are frequent forms when hypercalcaemia or hypercalciuria occur. Drugs used for treatment of systemic sarcoidosis can also cause renal damage. Due to its high heterogeneity, renal sarcoidosis can be difficult to treat. Glucocorticoids and various immunosuppressive treatments have been proven to be effective based on case series, but clinical trials are lacking. A treatment guideline for renal sarcoidosis is urgently needed. In this review article, we present an overview of the different forms of renal sarcoidosis and the diagnostic steps to confirm renal involvement; in addition, we provide insights on the management and available treatments. A better understanding regarding the pathogenesis of sarcoidosis is the key for the development of more specific, targeted therapies.

High-Risk Sarcoidosis: A Focus on Pulmonary, Cardiac, Hepatic and Renal Advanced Diseases, as Well as on Calcium Metabolism Abnormalities

Although sarcoidosis is generally regarded as a benign condition, approximately 20-30% of patients will develop a chronic and progressive disease. Advanced pulmonary fibrotic sarcoidosis and cardiac involvement are the main contributors to sarcoidosis morbidity and mortality, with failure of the liver and/or kidneys representing additional life-threatening situations. In this review, we discuss diagnosis and treatment of each of these complications and highlight how the integration of clinical, pathological and radiological features may help predict the development of such high-risk situations in sarcoid patients.

Tubulointerstitial Nephritis and Uveitis Syndrome in Pediatric Patients

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a disorder that was originally described in 1975. The syndrome, although diagnosed in all age ranges, is more frequently reported in pediatric patients. Diagnosis can be difficult, and its clinical spectrum is still being defined. In this article, we review the epidemiology, diagnosis, pathogenesis, clinical findings, prognosis, and treatment of both the ocular and renal disease. We comment on the current difficulties in diagnosis and study of the disease, its expanding clinical spectrum, and treatment strategies in pediatric patients.

Tumefactive Nonneoplastic Proliferative Pseudotumors of the Kidneys and Urinary Tract: CT and MRI Findings with Histopathologic Correlation

A diverse spectrum of pathologically distinct, nonneoplastic, proliferative conditions of the kidneys and urinary tract demonstrate a expansile growth pattern similar to that of neoplasms. The renal pseudotumors include myriad causes of infections as well as rare noninfectious causes such as sarcoidosis, amyloidosis, and immunoglobulin G4-related disease (IgG4-RD). Rare entities such as cystitis cystica, endometriosis, nephrogenic adenoma, and pseudosarcomatous myofibroblastic proliferation and distinct types of prostatitis comprise tumefactive nontumorous disorders that affect specific segments of the urinary tract. The pseudotumors of the kidneys and urinary tract demonstrate characteristic histopathologic and epidemiologic features, as well as protean clinical manifestations, natural history, and imaging findings. Many patients present with genitourinary tract-specific symptoms or systemic disease. Some cases may be incidentally discovered at imaging. Some entities such as perinephric myxoid pseudotumors, IgG4-RD, fibroepithelial polyp, and nephrogenic adenoma display specific anatomic localization and disease distribution. Imaging features of multisystem disorders such as tuberculosis, sarcoidosis, and IgG4-RD provide supportive evidence that may allow precise diagnosis. Fungal pyelonephritis, xanthogranulomatous pyelonephritis, IgG4-RD, actinomycosis, and endometriosis show markedly low signal intensity on T2-weighted MR images. Although some pseudotumors exhibit characteristic imaging findings that permit correct diagnosis, laboratory correlation and histopathologic confirmation are required for definitive characterization in most cases. A high index of suspicion is a prerequisite for diagnosis. Accurate diagnosis is critical for instituting optimal management while preventing use of inappropriate therapies or interventions. Surveillance CT and MRI are frequently used for monitoring the response of pseudotumors to therapy. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

A Rare Presentation of Sarcoidosis in a Young Male With Acute Renal Failure: A Case Report and Literature Review

Sarcoidosis presents in a variety of ways, but historically, renal involvement has been considered rare with an incidence of 0.7% and is seldom the presenting feature of the illness. Concomitant involvement of kidney and bone marrow is extremely rare. Atypical forms of presentation, such as in this case, may pose a true diagnostic challenge. A 20-year-old African-American male presented to the emergency department with vague symptoms including fatigue, malaise, anorexia, right-sided lower back pain, and nausea. Acute kidney injury was clearly evident, creatinine was 19.78 mg/dL (normal range 0.60-1.20 mg/dL), and BUN was 124.0 mg/dL (normal range 5.0-25.0 mg/dL). Laboratory results were also remarkable for leukopenia, microcytic anemia, hyperkalemia, anion gap metabolic acidosis, and non-PTH dependent hypercalcemia. Interestingly, urinalysis was equivocal and both chest x-ray (CXR) and abdominopelvic computed tomography (CT) scan were unrevealing. The patient was admitted to the hospital and required renal replacement therapy to stabilize his clinical condition while planning for a renal biopsy that was later performed. While awaiting pathological results, pancytopenia developed, and a bone marrow biopsy was then obtained. On further investigation, angiotensin-converting enzyme (ACE) turned out to be significantly elevated suggesting sarcoidosis. Renal biopsy showed moderate acute tubular injury, tubulitis, extensive interstitial edema, and infiltration by numerous non-caseating granulomas, which confirmed the diagnosis of sarcoidosis. Bone marrow histopathology revealed hypocellularity but no granulomatous infiltration. The patient remained largely asymptomatic throughout his hospital stay, with no signs or symptoms suggesting the involvement of other organs. High-dose corticosteroids were started and continued outpatient after discharge while still on hemodialysis. Pancytopenia resolved while on glucocorticoids and improvement in renal function was such that after roughly two months of steroids, renal replacement therapy was no longer necessary. Overall, kidney injury severe enough to require hemodialysis associated with pancytopenia in a previously healthy 20-year-old constitutes a rather rare sarcoidosis presentation. This highlights the importance of considering sarcoidosis as a possible cause of kidney and bone marrow dysfunction and emphasizes the need for timely biopsy to facilitate accurate diagnosis and early initiation of appropriate therapy to avoid delayed or inadequate care, especially considering that even severe damage is potentially reversible when identified early and treated promptly.

[Sarcoidosis]

Sarcoidosis is the most common granulomatous disease in northern Europe. A distinction is made between acute forms of sarcoidosis and chronic sarcoidosis. Chronic sarcoidosis can affect practically all organs but the lungs are affected in 90-95% of patients. The clinical appearance varies between asymptomatic and oligosymptomatic courses, which are diagnosed more by chance, to courses with acute organ failure. An extensive organ work-up is necessary at the time of the initial diagnosis in order to record the extent of organ involvement and to make appropriate treatment decisions. Asymptomatic courses with purely pulmonary sarcoidosis do not require treatment and can be observed over the course of the disease, whereas courses with extensive organ involvement or organ dysfunction require treatment. The treatment consists primarily of the administration of glucocorticoids. If the effect of the glucocorticoids is insufficient or if there are side effects, various immunosuppressive agents, including biologics can be added.

Renal disease in sarcoidosis patients in a German multicentric retrospective cohort study

INTRODUCTION

Sarcoidosis is a systemic granulomatous disease potentially affecting every organ system. Renal involvement is reportedly rare, and the evidence consists of case reports and cohort studies. Systematic investigations are scarce and show a varying prevalence ranging from <1% to 30-50%.

METHODS

We retrospectively analyzed data from patients with a recent diagnosis of sarcoidosis from five tertiary care centers focusing on renal sarcoidosis.

RESULTS

We analyzed data from 327 patients with sarcoidosis between 2001 and 2021. Of 327 patients, 109 (33.3%) had probable or definite renal sarcoidosis. 90 (27.5%) had histopathologic confirmation. 57 (64%) had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². The most prominent associated finding was an elevated soluble interleukin-2 receptor. Patients with renal sarcoidosis more frequently received glucocorticoids than other non-renal sarcoidosis patients (92% vs. 78%, p < 0.01). Also, azathioprine (38% vs. 16%, p < 0.001) and mycophenolate mofetil (5% vs. 1%, p < 0.05) were more frequently used in renal sarcoidosis compared to non-renal sarcoidosis, whereas methotrexate was used less frequently (7% vs. 17%, p < 0.05).

CONCLUSIONS

Our data of the largest cohort with biopsy-confirmed renal sarcoidosis demonstrate a higher prevalence (27.5% of all patients) than previously published with a relevant disease burden. The urinary findings in most cases were only mildly abnormal, and some patients did not have renal biopsy despite abnormal urinary results. A renal workup should be performed in all patients with a new diagnosis of sarcoidosis.

Sarcoidosis

Sarcoidosis is a disease of unknown cause characterized by granulomatous inflammation. Although the lung is almost universally involved, any organ can be affected. Complex pathogenesis and protean clinical manifestations are additional features of the disease. The diagnosis is one of exclusion, although the presence of noncaseating granulomas at disease sites is a prerequisite in most cases. The management of sarcoidosis requires a multidisciplinary approach, particularly when the heart, the brain, or the eyes are involved. The paucity of effective therapies and the lack of reliable predictors of disease behavior greatly contribute to making sarcoidosis a challenging disease to manage.

Renal replacement therapy in sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology. Kidney involvement in sarcoidosis may be present in up 25-30% of cases. An early diagnosis and prompt treatment with corticosteroids can improve the prognosis but rarely renal sarcoidosis can lead to kidney failure needing renal replacement therapy (RRT). Acute kidney injury (AKI) in sarcoidosis may be caused by granulomatous interstitial nephritis (GIN) or hypercalcemia. These disorders are usually clinically silent and may lead end stage renal disease (ESKD) if not diagnosed or detected too late. In patients with ESKD, dialysis and renal transplantation can offer results comparable to those observed in patients with other causes of kidney failure. Based on a review of literature, we present an overview of RRT in patients with AKI or chronic kidney disease (CKD) caused by sarcoidosis.

Hypercalciuria may predict better response to immunosuppressive therapy in renal sarcoidosis: a case series

BACKGROUND

Renal sarcoidosis is a rare cause of tubulointerstitial nephritits (TIN). The clinical and pathological characteristics, as well as outcomes, of renal sarcoidosis remain unclear.

METHODS

This single-center study retrospectively analyzed 18 patients affected by sarcoidosis with tubulointerstitial nephritis (TIN) and 53 patients with tubulointerstitial nephritis  not related to sarcoidosis. Patients were further stratified into the granulomatous (12 sarcoidosis and 6 non-sarcoidosis) and non-granulomatous (6 sarcoidosis and 47 non-sarcoidosis) TIN groups.

RESULTS

Half of the patients with renal sarcoidosis had signs of acute kidney injury at kidney biopsy, 94% of whom presented with extra-renal involvement. The prevalence of hypercalcemia, hypercalciuria, and elevated serum angiotensin-converting enzyme levels was 27.6%, 33.3%, and 31.3%, respectively. Renal sarcoidosis patients with eGFR < 30 mL/min/1.73 m2 scored higher for total chronic tubulointerstitial injury (p = 0.044) and glomerular sclerosis (p = 0.027). Compared to non-sarcoidosis patients, higher urinary calcium levels (for patients with GFR [Formula: see text] 40 mL/min/1.73 m2, p = 0.034), lower scores of acute tubular injury (p = 0.008), and more prominent glomerular sclerosis were observed in renal sarcoidosis. Similar characteristics of chronicity and hypercalciuria were also identified in granulomatous interstitial nephritis; however, interstitial inflammation was obvious (p = 0.001). Patients with renal sarcoidosis were initially treated with corticosteroids. Five patients receiving immunosuppressive agents showed better long-term renal recovery. High 24-h urine calcium (adjusted by weight) was identified as a factor associated with long-term remission.

CONCLUSION

Renal sarcoidosis is a systemic disease of insidious onset and chronic progression, sharing similar features of chronicity and hypercalciuria with granulomatous interstitial nephritis of other cause. Hypercalciuria may predict a better response to immunosuppressive therapy, presumably indicating active interstitial inflammation; thus, strengthened immunosuppression might be considered.

Renal sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology. The pathogenesis rests on an aberrant T cell response to unidentified antigens in individuals predisposed by genetic and environmental factors. Increased expression of polarized macrophages and disequilibrium between effector and regulator T cells contribute to the formation of noncaseating granulomas, that are frequently found in affected organs. The main kidney abnormalities in sarcoidosis are granulomatous interstitial nephritis (GIN) and hypercalcemia-related disorders. The clinical diagnosis is difficult. The outcome is variable, ranging from spontaneous remission to end-stage kidney disease (ESKD). Early diagnosis and prompt treatment with corticosteroids can improve the prognosis. Hypercalcemia may be responsible for acute kidney injury (AKI) caused by vasoconstriction of afferent arterioles. Complications of persistent hypercalcemia include nephrocalcinosis and renal stones. In patients with ESKD, dialysis and transplantation can offer results comparable to those observed in patients with other causes of kidney failure. Based on a review of the literature, we present an overview of the etiopathogenesis, the renal manifestations of sarcoidosis and their complications, management and prognosis.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Idiopathic granulomatous interstitial nephritis and isolated renal sarcoidosis: Two diagnoses of exclusion

Granulomatous interstitial nephritis is a rare finding in renal biopsy caused by drugs, infections, and inflammatory or autoimmune diseases. Idiopathic cases account for 18% of granulomatous interstitial nephritis in native kidneys. Sarcoidosis and drugs are the most common causes of granulomatous interstitial nephritis in Western countries, while in India tuberculosis prevails. Few cases of renal sarcoidosis without extrarenal involvement, that is, isolated renal sarcoidosis, have been reported. The diagnostic criteria of isolated renal sarcoidosis remain, however, unclear. Extrarenal sarcoidosis and other etiologies of granulomatous interstitial nephritis, in particular drug-related, have to be excluded. Some of these patients may develop extrarenal manifestations during follow-up. Changes in calcium and vitamin D metabolism are frequently observed in renal sarcoidosis and support its diagnosis. While non-necrotizing granulomas are a feature of sarcoidosis and drug-induced granulomatous interstitial nephritis, they also prevail in tuberculosis-associated granulomatous interstitial nephritis. Granulomatous interstitial nephritis caused by sarcoidosis and drugs usually responds to steroid therapy. A poor response to steroids may indicate an infectious etiology such as tuberculosis and should lead to a review of the initial diagnosis. This article gives an overview of the various etiologies of granulomatous interstitial nephritis, their frequency and histopathological characteristics, as well as potential biomarkers associated with renal sarcoidosis.

A Rare Case of Renal Sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder characterized by non-caseating granulomas in multiple organs. It most commonly involves lungs and it is very rare to find isolated cases affecting other organ systems with no associated pulmonary findings. We hereby present a case of a young 30-year-old male who was referred to the hospital by his primary medical doctor due to right eye pain secondary to iritis and acute kidney injury (AKI). His initial laboratory studies revealed anemia, AKI, mild hypercalcemia, and the urinary analysis revealed proteinuria. Imaging studies were negative and a kidney biopsy was performed and showed results from the biopsy that revealed diffuse tubulointerstitial disease with early fibrosis, widespread moderate inflammation, multifocal tubulitis, and focal aggregate of epithelioid cells suggestive of granuloma consistent with sarcoidosis. The patient was treated with prednisone. Renal involvement of sarcoidosis is extremely rare (around 0.7%). It has a wide spectrum of presentation including abnormal calcium metabolism, nephrolithiasis, nephrocalcinosis, and acute tubulointerstitial nephritis with or without granulomas. This is a unique case as it shows renal sarcoidosis without coexisting pulmonary finding of hilar lymphadenopathy on chest X-ray. There are very few reported cases of renal sarcoidosis in the literature and this case can add to the pool of those cases. It also emphasizes the need for urgent renal biopsy in the settings of AKI associated with mild to moderate proteinuria. Lack of availability of comprehensive research on the disease may lead to misdiagnosis and delay in treatment.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.

Case Report: Pediatric Renal Sarcoidosis and Prognostic Factors in Reviewed Cases

Background: Pediatric sarcoidosis is a complex inflammatory disorder with multisystemic manifestations. Kidney involvement in children is rare, and prognostic factors are unknown. Case Report and Methods: We report the case of a 16-year-old girl with multiorgan sarcoidosis and renal involvement. The patient presented with tubulointerstitial nephritis, acute kidney injury (AKI), chest CT disseminated noduli, granulomatous iridocyclitis, giant-cell sialadenitis, and arthralgia. The kidney biopsy revealed non-granulomatous interstitial nephritis. Treatment consisted of initial high-dose methylprednisolone pulse followed by oral prednisolone and methotrexate. Full remission was achieved. In addition, we performed a literature review using PubMed and analyzed data on pediatric renal sarcoidosis cases. Results: We identified 36 cases of pediatric sarcoidosis with renal involvement on presentation and data on the end-of-follow-up glomerular filtration rate (GFR). The data from the literature review showed that renal involvement was slightly more prevalent in males (60%). AKI was present in most of the described patients (84%). Oral prednisolone was used in 35 of 36 cases; in more severe cases, other immunosuppressants were used. We newly identified renal concentration impairment and granulomatous interstitial nephritis as factors with a clear trend toward GFR loss at the end of follow-up, emphasizing the importance of kidney biopsy in symptomatic patients. In contrast, higher GFR at presentation and hypercalcemia were rather favorable factors. According to the identified predictive factors, our patient has a good prognosis and is in remission. Conclusion: The factors indicating a trend toward an unfavorable renal outcome in pediatric sarcoidosis are renal concentration impairment and granulomatous interstitial nephritis at presentation, while a higher GFR is beneficial.

A case of granulomatous tubulointerstitial nephritis in a patient with pulmonary sarcoidosis

A clinical observation is presented of a patient with pulmonary sarcoidosis, who was diagnosed with kidney damage after three years with the development of chronic renal failure and the need for replacement therapy. A histological examination of the renal biopsy revealed a granulomatous process in the interstitial tissue, which was regarded as an extrapulmonary manifestation of sarcoidosis. Pulse therapy with glucocorticoids was prescribed and an attempt was made to reduce hemodialysis sessions.

Chronic Inflammatory Arthropathy Preceding Acute Systemic Manifestations of Sarcoidosis: A Possible Overlap of Idiopathic Juvenile Arthritis and Sarcoidosis

Sarcoidosis is a multisystem disease with unknown etiology, marked by T lymphocytes and macrophages agglomeration, which leads to the formation of noncaseating granulomas in the affected tissues. We describe a case of a 40-year-old black patient referred to our service for evaluation of nephrolithiasis and persistent elevation of plasma creatinine. He reported important weight loss, fever episodes, and abdominal and low back intermittent pain in the past 6 months. The investigation revealed elevated serum calcium level, hepatosplenomegaly, retroperitoneal lymphadenopathy, anemia, thrombocytopenia, and nephrolithiasis. The initial diagnostic hypothesis was lymphoproliferative disease, but the laparoscopic propaedeutic showed multiple white lesions on the liver surface, which biopsy identified as noncaseating granulomas with asteroid corpuscles, suggestive of sarcoidosis. He was treated with corticosteroids with significant improvement in symptoms and in calcium and creatinine levels. Besides, the patient presented a long-term large joints arthropathy, especially on the knees (with bilateral prosthesis), wrists, and ankles, of unknown etiology. We discuss the systemic manifestations of sarcoidosis related to the reported case, as well as the possible overlapping of idiopathic juvenile arthritis with sarcoidosis.

[18F-FDG positron emission tomography in non-oncological renal pathology: Current indications and perspectives]

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which provides anatomical and functional information. PET/CT is increasingly used in non-oncological nephrology since conventional radiological approaches after injection of contrast agents are relatively contra-indicated in patients with chronic kidney disease (CKD). PET/CT after i.v. injection of ¹⁸F-fluoro-deoxy-glucose (FDG) is not toxic and is characterized by a high sensitivity. The level of irradiation (∼5mSv) is acceptable. CKD does not significantly influence tissue uptake of ¹⁸F-FDG. The purpose of the present review aims at detailing the non-oncological indications of ¹⁸F-FDG PET/CT in general nephrology and after kidney transplantation. Particularly, ¹⁸F-FDG PET/CT appears useful in the diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease, as well as in the characterization of retroperitoneal fibrosis. In kidney transplant recipients, ¹⁸F-FDG PET/CT may help in the diagnostic work-up of suspected acute rejection, thereby eventually avoiding unnecessary kidney transplant biopsy. Perspectives in ¹⁸F-FDG PET/CT imaging are discussed, including innovative approaches of image analysis.

Ultrasound imaging of abdominal sarcoidosis: State of the art

Since it has been recognized that sarcoidosis (SA) is not an exclusive disorder of the lungs but can also affect other organs such as the liver and spleen, efforts have been made to define specific imaging criteria for the diagnosis of the single organ involvement, and the concept has been reinforced that the exclusion of alternative causes is important to achieve the correct diagnosis. Ultrasound (US) is a useful tool to evaluate patients with suspected abdominal SA, such as of the liver, spleen, kidney, pancreas and other organs, showing findings such as organomegaly, focal lesions and lymphadenopathy. While the diagnosis of abdominal SA is more predictable in the case of involvement of other organs (e.g., lungs), the problem is more complex in the case of isolated abdominal SA. The recent use of contrast-enhanced ultrasound and endoscopic ultrasound elastography has provided additional information about the enhancement patterns and tissue rigidity in abdominal SA. Here we critically review the role of US in abdominal SA, reporting typical findings and limitations of current evidence and by discussing future perspectives of study.