Current approach to diagnosis and management of retroperitoneal fibrosis

Atypical Presentation of Retroperitoneal Fibrosis Causing Colonic Obstruction: A Case Report

Retroperitoneal fibrosis (RPF), also referred to as Ormond's disease, is a rare fibroinflammatory condition characterized by abnormal fibrous tissue deposition in the retroperitoneal space, which traditionally presents with ureteral obstruction. Nonetheless, our case report showcases an exceptional instance involving a 70-year-old female patient who presented with symptoms suggestive of colonic obstruction, an unusual presentation that is not commonly associated with RPF. Although RPF has established associations with autoimmune conditions such as immunoglobulin G4-related disease and systemic lupus erythematosus, its connection to colonic obstruction remains undocumented in the medical literature. Our patient is a 70-year-old female who presented with constipation, anemia, and fecal occult blood. Her past medical history included a hysterectomy due to fibroids, right breast lumpectomy, type 2 diabetes mellitus, subclinical hyperthyroidism, hypertension, and obesity. Upon physical examination, the patient's abdomen appeared protuberant but was non-tender to palpation. Bowel sounds were normal, and there was no distension. Notably, there was no tenderness in the right or left costovertebral angles, nor was there any guarding. Workup with colonoscopy could not be completed due to the inability to pass a colonoscope beyond the rectosigmoid junction. Further workup with barium enema confirmed an apple core lesion seen in the rectosigmoid concerning for a neoplastic or inflammatory process. Finally, a computed tomography scan of the abdomen and pelvis showed a 7.1 cm right pelvic mass attached to the bladder and cecum, moderate right hydroureteronephrosis, and a 5.2 cm left adnexal mass with soft tissue changes narrowing the sigmoid colon. The next step was to take the patient for an exploratory laparotomy. During exploratory laparotomy, extensive adhesions and desmoplastic reactions were observed in the pelvic region, involving the sigmoid colon, bladder, cecum, and appendix. Two firm masses were identified in the retroperitoneum, one located in the left lower quadrant (LLQ) adherent to the posterior wall of the sigmoid colon and one in the right lower quadrant (RLQ) adherent to the posterior wall of the cecum. Three specimens were sent to pathology for further examination: a portion of the sigmoid colon, a resection from the RLQ mass, and a resection from the LLQ mass. Pathology reported dense fibrotic masses with abscess-like formation, reactive in nature and of unclear etiology, and negative for malignancy. They were negative for fibromatosis (β-catenin negative), and IgG4+/IgG+ was approximately 5%. Interestingly, the LLQ mass also contained remnants of the fallopian tube and ovary and benign cystic changes. This case report presents a unique and atypical presentation of RPF, deviating from the conventional presentation of ureteral obstruction. The patient's initial symptoms suggested colonic obstruction, a clinical scenario rarely linked to RPF. This case underscores the significance of considering diverse clinical presentations when diagnosing RPF, thereby expanding our comprehension of the condition's clinical spectrum and ultimately refining patient care and management.

Role of transduodenal endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) for diagnosis of retroperitoneal fibrosis (Ormond's disease)

BACKGROUND

Retroperitoneal fibrosis (RPF), often referred to as Ormond's disease when it is of idiopathic origin, is a rare disease characterized by the presence of inflammatory infiltrates and periaortic masses in the retroperitoneum. For a definite diagnosis, a biopsy and subsequent pathological examination is required. Currently accepted methods for retroperitoneal biopsy include open, laparoscopic, or CT-guided approaches. However, transduodenal endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) for diagnosis of RPF has attracted only little attention in the literature.

CASE REPORTS

We report two male patient cases who presented with leukocytosis, elevated C-reactive protein, and a suspicious retroperitoneal mass of unknown origin on computed tomography. One patient also reported left lower quadrant pain, whereas the other patient suffered from back pain and weight loss. In both patients, idiopathic RPF was successfully diagnosed by using transduodenal EUS-FNA/FNB with 22- and 20-gauge aspiration needles. Histopathology revealed dense lymphocytic infiltrates and fibrosis. The procedures lasted approximately 25 and 20 minutes, respectively, and in both patients no serious adverse events occurred. Treatment included steroid therapy and administration of Azathioprine.

CONCLUSION

We demonstrate that using EUS-FNA/FNB to diagnose RPF is a feasible, fast, and safe method, which should always be considered as a first-line diagnostic modality. Hence, this case report emphasizes that gastrointestinal endoscopists are likely to play an important role in the setting of suspected RPF.

Lower Urinary Tract Disorders as Adverse Drug Reactions-A Literature Review

A potential complication of pharmacotherapy for a given patient is the possibility of various side effects of drugs, which are manifested in many ways and constitute iatrogenic causes of diseases. Among the systemic side effects of drugs, there are also those involving the urinary tract, although these are less reported in the literature. The use of numerous drugs-especially of anticholinergics or drugs with anticholinergic potential, opioid analgesics, non-steroidal anti-inflammatory drugs, antidepressants, first-generation antipsychotics (classic neuroleptics) and selected cardiovascular drugs (beta-blockers, thiazides potassium-sparing diuretics, statins), as well as others-may increase the risk of developing urological disorders, such as urinary retention or incontinence, urinary tract infections, urolithiasis, erectile dysfunction in men and retroperitoneal fibrosis. The purpose of this paper is to characterise the abovementioned drug-induced disorders of the lower urinary tract on the basis of a non-systematic literature review.

Combined therapy of prednisone and mTOR inhibitor sirolimus for treating retroperitoneal fibrosis

OBJECTIVES

Retroperitoneal fibrosis (RPF) is a rare autoimmune disease with fibrous tissue growth and inflammation in retroperitoneum. Its current treatments involve long-term uptake of glucocorticoids (e.g., prednisone) for controlling inflammation; however, side effects are common. We strived for an improved therapy for fibrosis remission while reducing side effects.

METHODS

We surveyed gene-disease-drug databases and discovered that mammalian target of rapamycin (mTOR) was a key signalling protein in RPF and the mTOR inhibitor compound sirolimus affected many RPF pathways. We designed a therapy combining a gradual reduction of prednisone with a long-term, stable dosage of sirolimus. We then implemented a single-arm clinical trial and assessed the effects in eight RPF patients at 0, 12 and 48 weeks of treatment by measuring fibrous tissue mass by CT, markers of inflammation and kidney functions by lab tests, immune cell profiles by flow cytometry and plasma inflammatory proteins by Olink proteomics.

RESULTS

With the combined therapy, fibrous tissue shrunk about by half, markers of acute inflammation reduced by 70% and most patients with abnormal kidney functions had them restored to normal range. Molecularly, fibrosis-related T cell subsets, including TH2, TH17 and circulating TFH cells, were reduced and tumour necrosis factor and related cytokines restored to healthy levels. No severe long-term side effects were observed.

CONCLUSIONS

Our combined therapy resulted in significant fibrosis remission and an overall regression of the immune system towards healthy states, while achieving good tolerance. We concluded that this new therapy had the potential to replace the steroid monotherapy for treating RPF.

Indications for and results of renal autotransplantation

PURPOSE OF REVIEW

To understand the indications and outcomes of renal autotransplantation, and when to consider this unique procedure for patients.

RECENT FINDINGS

Renal autotransplantation confers acceptably low rates of graft failure and prevents need for long-term dialysis. Renal autotransplantation remains an important management strategy in very select patients for complex renovascular disease, ureteral stricture disease, ureteral trauma, upper urinary tract urothelial carcinoma, renal cell carcinoma, and Loin-Pain Hematuria Syndrome. With advancements in minimally invasive procedures, the application of renal autotransplantation for refractory stone disease is rare but exists. Robot-assisted laparoscopic renal autotransplantation demonstrates reproducible graft success and complication rates with improved perioperative outcomes (ex. hospital length of stay) - though comparative studies are lacking. Patients would benefit from a multidisciplinary approach from renal transplant surgeons, vascular surgeons, urologists, nephrologists, dieticians, pain management providers, social workers, and psychiatrists.

SUMMARY

In experienced hands, renal autotransplantation is a reasonable treatment approach for complex and refractory renal vascular disease, Loin-Pain Hematuria Syndrome, ureteral strictures and trauma, upper urinary tract malignancy, and stone disease in highly select patients.

Network pharmacology and bioinformatics study on the treatment of renal fibrosis with persicae semen-carthami flos drug pair

To use network pharmacology and bioinformatics technology to reveal the mechanism of persicae semen-carthami flos drug pair in the treatment of renal fibrosis (RF). Compounds in traditional Chinese medicine were obtained through the Herb database. Appropriate compounds and corresponding drug targets were screened out based on the 5 rules of Lipinski and pharmacokinetics. Screening of suitable disease miRNAs by microarray chips in the GEO database. Find differentially expressed genes by analyzing miRNAs. Protein-protein interaction analysis and enrichment analysis of therapeutic targets were performed using String database and Omicshare platform. Molecular docking via the DockThor platform. A total of 28 drug compounds and 228 drug targets were screened in this study. A total of 9 miRNAs and 6649 disease targets were obtained by GEO2R software analysis. Finally, 97 therapeutic targets were obtained. A total of 1124 Gene Ontology enrichment analysis results were obtained. Therapeutic targets play multiple roles in biological processes, molecular functions, and cellular organization. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the persicae semen-carthami flos drug pair played a role in the treatment of RF mainly through calcium signaling pathway, pathways in cancer, cAMP signaling pathway, and other pathways. Molecular docking showed that the traditional Chinese medicine compounds had good binding ability to the target. Persicae semen and carthami flos play a role in the treatment of RF through multiple targets and multiple pathways. It provides ideas and references for follow-up research and new drug development.

Retroperitoneal Fibrosis: Still a Diagnostic Challenge

Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disorder usually involving the abdominal aorta and surrounding structures. It is divided into primary (idiopathic) and secondary RPF. Primary RPF can be immunoglobulin (Ig) G4-related disease or non-IgG4-related disease. Recently, there has been a rise in case reports regarding the topic, but awareness about the disease is still far from ideal. Hence, we present the case of a 49-year-old female who had repeated admissions for chronic abdominal pain attributed to chronic alcoholic pancreatitis. She had a medical history significant for psoriasis and surgical history significant for cholecystectomy. Her computed tomography (CT) scans on each admission for the last year showed some signs of RPF, but it was never considered the primary etiology of her chronic symptoms. We also obtained magnetic resonance imaging (MRI) which did not show any underlying malignancy but showed the progression of her RPF. She was started on a steroid regimen, which significantly improved her symptoms. She was diagnosed with idiopathic RPF due to unclear etiology, although her underlying risk factors, including psoriasis, past surgeries, and pancreatitis-associated inflammation, were considered predisposing factors. Idiopathic RPF accounts for more than two-thirds of total cases of RPF. Patients with autoimmune diseases can overlap with other autoimmune disorders. For non-malignant RPF, medical management with 1mg/kg/day steroids is deemed effective. Still, there is a lack of prospective trials and consensus for guidelines on treating RPF. The follow-up involves laboratory tests, including erythrocyte sedimentation rate, C-reactive protein, and CT or MRI in an outpatient setting to identify treatment response and relapse. There is a need for more streamlined guidelines to diagnose and manage this disease.

Serum IgG4 Concentration Is a Potential Predictive Biomarker in Glucocorticoid Treatment for Idiopathic Retroperitoneal Fibrosis

Objectives: To evaluate the management and outcome of idiopathic retroperitoneal fibrosis (iRPF) in Japan, and to identify its clinical biomarker. Methods: We retrospectively analyzed 129 patients with iRPF treated between January 2008 and May 2018 at 12 university and related hospitals. Patients treated with glucocorticoid were analyzed to identify a predictive biomarker. These patients were classified into three groups according to overall effectiveness (no change: NC, complete response: CR, and partial response groups: PR), and each parameter was compared statistically. Results: Male–female ratio was 5:1, and median age at diagnosis was 69 (33–86) years. Smoking history was reported in 59.6% of the patients. As treatment, 95 patients received glucocorticoid therapy with an overall response rate of 84%. As a result, serum concentration of IgG4 was significantly decreased in NC group compared with the other two groups (56.6 mg/dL vs. 255 mg/dL, 206 mg/dL, p = 0.0059 and 0.0078). ROC analysis was performed between the nonresponder (NC) and responder groups (CR + PR) to identify the cut-off value of serum IgG4 as a predictive marker. As a result, AUC of 0.793 was confirmed. Conclusions: Pre-treatment serum IgG4 concentration may have potential as a predictive biomarker of steroid treatment.

Comparison of laparoscopic and open ureterolysis for retroperitoneal fibrosis: Results from a tertiary referral center

OBJECTIVES

To compare the surgical outcomes of open and laparoscopic ureterolysis procedures in patients requiring surgical treatment for ureteral obstruction caused by retroperitoneal fibrosis.

MATERIALS

This study was designed retrospectively. The clinical records of patients who underwent ureterolysis between January 2005 and April 2019 due to ureteral obstruction caused by retroperitoneal fibrosis were examined. According to the type of surgery, the patients were divided into two groups as Group 1 (open ureterolysis) and Group 2 (laparoscopic ureterolysis). Demographic features, preoperative-postoperative renal functions, duration of follow-up with ureteral stents, and perioperative-postoperative complications were examined. The requirement of ureteral stent placement during the follow-up period was accepted as unsuccessful ureterolysis.

RESULTS

Ureterolysis was performed in 13 patients and 23 renal units. Eleven of these patients were male and two were female. The median age of the patients was 54 (44-68) years. There were six patients and 12 renal units in Group 1 and seven patients and 11 renal units in Group 2. Postoperatively, a total of four patients (30%) had minor complications (Clavien-Dindo 1-2) and one patient had a major complication (Clavien-Dindo 3a). Ureterolysis was determined to be successful in 21 of the renal units (91%) [11/12 (92%) in Group 1 vs 10/11 (91%) in Group 2]. No statistically significant difference was found between the groups in terms of the success and complication rates (p=1 and p=0.529, respectively). Postoperative hospitalization length and recovery time to return to normal preoperative activities were significantly shorter in Group 2 than Group 1 (p=0.011 and p=0.041, respectively).

CONCLUSIONS

The success and complication rates were similar between the open and laparoscopic methods for ureterolysis. Laparoscopic approach was advantageous over open approach in terms of postoperative hospitalization length and recovery time to return to normal preoperative activities.

Mixed connective tissue disease and idiopathic retroperitoneal fibrosis: A rare but important association

Idiopathic Retroperitoneal fibrosis (RPF) is a fibro-inflammatory disease. In patients with known mixed connective tissue disease (MCTD) it has rarely been described. Our case illustrates a unique presentation of RPF in a patient with MCTD. We emphasise possible links between the two disease processes and the high level of clinical suspicion required to make a diagnosis.

Retroperitoneal fibrosis, a rare entity with urorenal and vascular subtypes - preliminary data

Introduction

Retroperitoneal fibrosis (RPF) is a rare disease associated with the formation of hard inflammatory and fibrous tissue in the retroperitoneum. Taking into consideration the fact that RPF is a rare disease with different subtypes, we compared the basal clinical and biochemical characteristics of the vascular and urorenal subtypes.

Patients and methods

From January 2005 until December 2021, 27 patients were identified as vascular subtype (18 males) and 11 as urorenal subtype (9 males).

Results

Patients with a primary urorenal origin had significantly worse kidney function as reflected by serum creatinine and eGFR (both p < 0.001); they also had higher serum cholesterol (p < 0.01). Hypertension, diabetes, hyperlipidemia and nicotinism were significantly more prevalent in vascular subtype (all p < 0.001).

Conclusion

Vascular subtype is more prevalent in our study with more cardiovascular risk factor present. Due to the diversity of symptoms, diagnosis of RPF becomes a challenge for specialists as well as therapy.

Retroperitoneal fibrosis as a postoperative complication following renal transplantation in cats

OBJECTIVES

The aim of this report was to describe the clinical signs, diagnostic imaging findings, surgical management, histopathological findings, outcome and possible risk factors for cats that developed retroperitoneal fibrosis (RPF) following renal transplantation.

METHODS

Medical records of cats that underwent renal transplantation and developed clinically significant RPF between 1995 and 2019 were reviewed.

RESULTS

Eighty-one cats underwent 83 renal transplantations. Of these 81 cats, six developed clinically significant RPF. For all six cats, renal transplantation was performed using cold organ preservation solution and ureteral papilla implantation. Immunosuppression protocol included ciclosporin and prednisolone. All cats had at least one subtherapeutic trough ciclosporin level (<250 ng/ml) in the postoperative period. Cats presented with moderate-to-severe azotemia 39-210 days following renal transplantation. Abdominal ultrasonography and contrast pyelography revealed various degrees of hydroureter and hydronephrosis of the transplanted kidney. Surgical examination revealed a layer of dense fibrous tissue surrounding the transplanted kidney, ureter and bladder resulting in ureteral obstruction. Ureteral obstruction was managed by reimplantation of the proximal ureter or renal pelvis to the bladder. Histopathologic examination of the fibrous tissue and affected portion of the distal ureter revealed fibrous connective tissue with lymphoplasmacytic infiltration and perivascular inflammation suggestive of an autoimmune type reaction. Of the six cats, two died within 5 days after revision surgery, two developed signs consistent with recurrent partial ureteral obstruction (40 and 41 days after revision), one was euthanized 6 years later for an unrelated disease and one was lost to follow-up.

CONCLUSIONS AND RELEVANCE

The incidence of RPF in this population of cats was relatively low (7%), but still represents a significant cause of morbidity and mortality. The cause of RPF remains unknown, although investigation into suboptimal immunosuppression as a potential cause for local rejection reaction is warranted.

Differences of clinicopathological features between IgG4-related and non-IgG4-related idiopathic retroperitoneal fibrosis

OBJECTIVE

To evaluate the clinical and pathological features of IgG4-related and non-IgG4-related idiopathic retroperitoneal fibrosis (IRF) according to the latest classification criteria for IgG4-related disease in 2019.

METHODS

Patients with IRF confirmed by histological examination from our hospital between 2000 and 2020 were selected in this study. Medical records of all patients were reviewed by independent researchers. Retroperitoneal specimens were obtained for hematoxylin & eosin staining, elastic-collagenous fiber staining, and immunohistochemical analysis. The clinical and pathological features between IgG4-related and non-IgG4-related IRF were analyzed.

RESULTS

A total of 105 patients were included with 77 in the IgG4-related group and 28 in non-IgG4-related group. The ratio of male to female patients and the incidence of acute renal failure were significantly higher in the IgG4-related group than in the non-IgG4-related group. Elevated erythrocyte sedimentation rate and C-reactive protein were more common and the recurrence rate was significantly higher in the IgG4-related group than in the non-IgG4-related group. Radiographically, the ureter was more easily involved by retroperitoneal soft tissue in the IgG4-related group. Histologically, there were no significant differences in the incidence of dense lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis between the two groups except for the IgG4 staining.

CONCLUSIONS

Idiopathic retroperitoneal fibrosis can be classified into IgG4-related and non-IgG4-related subtypes. There were no significant pathological differences between the two subtypes of IRF, except for the IgG4 staining. Patients with the IgG4 subtype tended to be more likely to be male, have a higher inflammatory index, and be more likely to have recurrence.

The contribution of oncovascular surgery in a young patient with idiopathic retroperitoneal fibrosis

Surgical resection remains the cornerstone for the treatment of oncological disease. When a critical arterial or venous structure is involved in a tumor mass, successful relief of symptoms and long-term oncological control are achieved through careful preoperative planning by an interdisciplinary team that necessarily includes a vascular surgeon. We describe the involvement of a vascular surgeon in the oncology of a 22-year-old woman, who is diagnosed with idiopathic retroperitoneal fibrosis.

Retroperitoneal fibrosis masquerading as pelvi-ureteric junction obstruction - Laparoscopic management

Introduction

Retroperitoneal fibrosis (RPF) is a rare fibro-inflammatory condition which is characterized by development of extensive fibrosis throughout the retroperitoneum. It is classically centred over the anterior surface of the fourth and fifth lumbar vertebrae. It results in entrapment and extrinsic compression of retroperitoneal structures.

Presentation of the case

We present the case of a 69 years old man who was reported to have right pelvi - ureteric junction obstruction on computed tomography, but turned out to have RPF.

Discussion

Retroperitoneal fibrosis commonly causes obstructive uropathy (either unilateral, bilateral or progressing from unilateral to bilateral) and if untreated, renal failure. It has high response/remission rates to glucocorticoid therapy. However, relapse rates are also high. Hence, close surveillance with serial laboratory and imaging investigations, after achieving remission, is key to long term disease control.

Conclusion

Although classical imaging findings, supportive laboratory markers and suggestive/diagnostic histopathology appearances for RPF are well documented, its accurate preoperative diagnosis is not always an assured certainty.

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This case is unique in that the original plan to perform a laparoscopic pyeloplasty, purportedly for right pelvi-ureteric junction obstruction; was aborted ‘on table’ and a laparoscopic ureterolysis performed, instead.

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Though ureteral involvement is bilateral in most cases of retroperitoneal fibrosis, this case is rare and unique in that the patient had unilateral involvement of his ureter (right sided).

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Periaortic fibro-inflammatory mass at the level of the lumbar vertebrae is the hallmark of primary / idiopathic retroperitoneal fibrosis. However in this case, no such imaging finding was noted. Instead, the patient had just obvious unilateral (ride sided) disease on pre-operative imaging.

[SIGNIFICANCE OF IgG4 IN IDIOPATHIC RETROPERITONEAL FIBROSIS]

(Objective)Retroperitoneal fibrosis is largely divided into the idiopathic and secondary types. Some idiopathic cases include IgG4-related diseases, which are often similar to malignant diseases, such as lymphoma and sarcoma. The diagnostic criteria for IgG4-related disease are used and pathologic examination is necessary for a definitive diagnosis of IgG4-related retroperitoneal fibrosis. The first choice of treatment for IgG4-related retroperitoneal fibrosis is steroid administration, but no consensus has been established regarding its dose and tapering schedule. We investigated the significance of IgG4 in diagnosis and treatment of idiopathic retroperitoneal fibrosis. (Patients and methods)We examined 14 cases diagnosed as idiopathic retroperitoneal fibrosis between April 2013 and March 2019. Serum IgG4 was measured at the time of diagnosis in 13 cases, and changes over time in serum IgG4 before and after the induction of steroid therapy were measured in 6 cases. Computed tomography-guided biopsy was performed on 4 cases. (Results)Of all cases, 1 patient was diagnosed as IgG4-related retroperitoneal fibrosis and 5 patients were classified as possible group. Ten patients were administered steroid therapy. Percutaneous nephrostomy tube was placed in 3 patients and was removed in 2 of these patients after steroid therapy. The serum high levels of IgG4 were confirmed in all 4 patients who were classified into the possible group and who were treated with steroids. (Conclusion)Although histologic examination is necessary for the diagnosis of retroperitoneal fibrosis, tissue collection by open or laparoscopic surgery is highly invasive. CT-guided biopsy may be useful in high-risk cases, such as elderly patients on anticoagulation. After excluding other diseases in high-risk cases, response to empiric steroid therapy may be diagnostic. In the possible group, changes in serum IgG4 levels may reflect the disease condition and might be useful in determining the maintenance dose of steroids.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [¹⁸F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [¹⁸F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Retroperitoneal Fibrosis after Chronic Abscesses of Silicone Fluid Fillers in a Case of Gluteal Augmentation

Filler injection or implantation is a progressing revolutionary subject. Although the widely available kinds in many implications are considered safe, post filler adverse events are not uncommon. These reactions range from mild reactions such as edema or erythema to detrimental reactions such as recurrent infected granuloma or vascular occlusion, which are predominantly related to non-FDA approved materials. Here, we presented a patient with a significant history of gluteal augmentation using unlicensed silicone who developed extensive retroperitoneal fibrosis complicated by deep venous occlusions and obstructive uropathy.