Imaging of uncommon retroperitoneal masses

Retroperitoneal leiomyosarcoma mimicking an ovarian tumor diagnosed using a negative ovarian pedicle sign

Retroperitoneal leiomyosarcoma (RPLMS) is rare and usually presents as a large abdominal mass with poor clinical symptoms. Radiological findings of an RPLMS arising in the pelvis of a woman resemble those of adnexal tumors. Herein, we present a case of RPLMS mimicking an adnexal tumor which was differentiated from having an ovarian origin as the right ovarian vein was passing through the tumor but there was no direct vascular connection with the tumor. Therefore, it is important to identify the ovarian vein to distinguish between these tumors.

Value of Non-Contrast-Enhanced Vessel Wall MR Imaging in Assessing Vascular Invasion of Retroperitoneal Tumors

BACKGROUND

Due to their location and growth patterns, retroperitoneal tumors often involve the surrounding blood vessels. Clinical decisions on a proper treatment depend on the information on this condition. Evaluation of blood vessels using non-contrast-enhanced vessel wall MRI may provide noninvasive assessment of the extent of tumor invasion to assist clinical decision-making.

PURPOSE

To investigate the performance and potential of non-contrast-enhanced vessel wall MRI in evaluating the degree of vessel wall invasion of retroperitoneal tumors.

STUDY TYPE

Prospective.

POPULATION

Thirty-seven participants (mean age: 60.59 ± 11.77 years, 59% male) with retroperitoneal tumors close to vessels based on their diagnostic computer tomography.

FIELD STRENGTH/SEQUENCES

3 T; vessel wall MRI sequences: two-dimensional T2-weighted MultiVane XD turbo spin-echo (2D-T2-MVXD-TSE) and three-dimensional T1-weighted motion sensitized driven equilibrium fat suppression turbo spin-echo (3D-T1-MSDE-TSE) sequences; conventional MRI sequences: T2-weighted fat suppression turbo spin-echo (T2-FS-TSE), T2-weighted turbo spin-echo (T2-TSE), modified Dixon T1-weighted fast field echo (T1-mDixon-FFE), and diffusion-weighted echo planar imaging (DWI-EPI) sequences.

ASSESSMENT

All patients underwent preoperative imaging using both non-contrast conventional and vessel wall MRI sequences. Images obtained from conventional and vessel wall MRI sequences were evaluated independently by three junior radiologists (3 and 2 years of experience in reading MRI) and reviewed by one senior radiologist (25 years of experience in reading MRI) to assess the degree of vessel wall invasion. MRI were validated results from the clinical standard diagnosis based on surgical confirmation or histopathological reports. Interobserver agreement was determined based on the reports from three readers with similar years of experiences. Intraobserver variability was assessed based on categorizing and recategorizing the vessels of 37 patients 1 month apart.

STATISTICAL TESTS

Intra-class correlation efficient (ICC), Chi-square test, McNemar test, area under the receiver-operating characteristic curve (AUC), Delong test, P < 0.05 was considered significant.

RESULTS

The accuracy of vessel wall MRI (91.96%, 95% CI: 85.43-95.71; 103 of 112) in detecting the degree of vessel wall invasion was significantly higher than that of conventional MRI (75%, 95% CI: 66.24-82.10; 84 of 112). The interobserver variability or reproducibility in categorization of the degree of vascular wall invasion was good in evaluating images from conventional and vessel wall MRI sequences (ICC = 0.821, 95% CI: 0.765-0.867 and ICC = 0.881, 95% CI: 0.842-0.913, respectively).

DATA CONCLUSION

Diagnosis of vessel wall invasion of retroperitoneal tumors and assessment of its severity can be improved by using non-contrast-enhanced vessel wall MRI.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 3.

An infrequent case of retroperitoneal synovial sarcoma

Synovial sarcoma (SS) is an uncommon malignant tumor, ranking third in prevalence within the soft tissue sarcomas group. The vast majority of synovial sarcomas are present in the extremities, with only 15% developing in the retroperitoneal space. Retroperitoneal synovial sarcoma (RSS) is an infrequent case of SS, with only about 20 cases reported in the literature. Diagnosing RSS before treatment remains challenging because of its nonspecific clinical symptoms. The disease is often detected at a later stage, leading to additional damage to other organs as well as complicated and ineffective treatment. Consequently, the 5-year survival rate is only 20%-29%. This report introduces a case of RSS in a 19-year-old male patient with imaging characteristics on computed tomography (CT) and magnetic resonance (MR).

Retroperitoneum revisited: a review of radiological literature and updated concept of retroperitoneal fascial anatomy with imaging features and correlating anatomy

PURPOSE

Spread of disease in the retroperitoneum is dictated by the complex anatomy of retroperitoneal fasciae and is still incompletely understood. Conflicting reports have led to insufficient and incorrect anatomical concepts in radiological literature.

METHODS

This review will discuss previous concepts prevalent in radiological literature and their shortcomings will be highlighted. New insights from recent anatomical and embryological research, together with imaging examples, will be used to clarify patterns of disease spread in the retroperitoneum that remain unexplained by these concepts.

RESULTS

The fusion fascia and the renal fascia in particular give rise to planes and spaces that act as vectors for spread of disease in the retroperitoneum. Some of these planes and structures, such as the caudal extension of the renal fascia, have previously not been described in radiological literature.

CONCLUSION

New insights, including the various fasciae, potential spaces and planes, are incorporated into an updated combined retroperitoneal fascial concept.

A Rare Case of Retroperitoneal Tumefactive Fibroinflammatory Lesion Related to IgG4-Sclerosing Disease

We present a unique case of a retroperitoneal tumefactive fibroinflammatory lesion related to IgG4-sclerosing disease; it is a rare manifestation of the IgG4-related disease, which usually causes diffuse fibrosis when located in the retroperitoneum, rather than mass-like lesions. A 49-year-old man presented to the emergency department complaining of abdominal pain and vomiting. Subsequent testing with abdominal ultrasound, CT, and MRI revealed a large retroperitoneal mass of unknown origin, heterogenous, with a concentric circles pattern best visualized in MRI. The lesion was resected, and the histological and immunohistochemical studies revealed an IgG4-related tumefactive fibroinflammatory lesion of the retroperitoneum.

Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts

INTRODUCTION

Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging.

CONCLUSION

Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Primary giant hydatid cyst of the retroperitoneum: Diagnosis and therapeutic approaches

INTRODUCTION AND IMPORTANCE

Primary hydatid cyst of the retroperitoneum is an exceedingly rare manifestation of hydatid disease. Diagnosis proves challenging due to nonspecific symptoms, and the condition is typically not suspected when facing a retroperitoneal cystic mass, necessitating awareness among clinicians and surgeons, particularly in endemic regions.

CASE PRESENTATION

A 45-year-old male with a three-month history of progressive abdominal enlargement and pain. Living in a rural area, he exhibited a 30 cm, well-defined retroperitoneal cyst, with no guarding confirmed by CT-scan, with characteristic daughter cysts. The diagnosis of primary retroperitoneal hydatid cyst was supported by positive hydatid serology and eosinophilia. Surgical intervention was crucial, and a complete pericystectomy, with 4 cm of pericyst on the aorta due to safety concerns, was performed after three months of preoperative albendazole-based treatment. The postoperative course was uneventful, and a two-year follow-up revealed no recurrence.

CLINICAL DISCUSSION

The prevalence of hydatid disease in North Africa is high, yet retroperitoneal cases are rare. The difficulty to diagnosis retroperitoneal masses, underscores the importance of precise patient evaluation and detailed imaging analysis. Percutaneous puncture is contraindicated due to the risk of dissemination, highlighting even more the significance of accurate preoperative diagnosis. Surgery, coupled with Albendazole treatment, remains the gold-standard, associated with meticulous intraoperative precautions to prevent disease dissemination.

CONCLUSION

Primary retroperitoneal hydatid cyst is rare. Diagnosis is difficult. Precise determination of patient's background and detailed analysis of imaging findings are mandatory. Percutaneous puncture is forbidden as it leads to disease spreading or even anaphylactic shock. Surgical excision is the gold-standard.

Clinical characteristics and management of primary retroperitoneal sarcoma: A literature review

Retroperitoneal sarcoma (RPS) is a rare tumor classified into many histological types. It is also often detected only after it has grown to a considerable size and requires extensive resection of the surrounding organs, making it difficult to offer optimal patient-tailored management. Evidence supporting specific treatment modalities for RPS is insufficient, owing to its rarity. The Japanese clinical practice guidelines for RPS were published in December 2021, with the aim of accumulating existing evidence and indicating the optimal practice for RPS. These guidelines provide important clinical questions (CQs) concerning the diagnosis and treatment of RPS. This review, with a particular focus on primary RPS, attempts to introduce clinical problems in the diagnosis and treatment of RPS and to assess those problems along with the CQs in the guidelines. According to these guidelines, although chemotherapy and radiotherapy are expected to have therapeutic effects, the level of evidence to support these treatments is not very high at present. Accordingly, complete resection of the tumor is the first and only option for managing primary RPS. However, as with other tumors, the demand for multidisciplinary treatment for RPS is increasing. These guidelines will undoubtedly represent a milestone in clinical practice in relation to RPS in the future, and further evidence is expected to be accumulated based on the CQs that have been proposed.

Primary retroperitoneal squamous cell carcinoma: a literature review

PURPOSE

Retroperitoneal squamous cell carcinoma is an extremely rare histological variant of retroperitoneal tumors. The exact etiology and origin of the same is still unknown. To date, only a few case reports have been published in the literature. Due to rarity, standard treatment protocol is not available. The article aims to review the literature and treatment options available for this uncommon entity, based on available data.

METHODS

We searched the databases like PubMed, PubMed Central, Scopus, and Google Scholar with the keywords "Squamous cell carcinoma" and "retroperitoneal tumors". Peer-reviewed and recent articles were screened.

RESULTS

Seven relevant articles comprising 14 cases were found. Due to the small number of reports, tabulation of treatment details and outcome was done. Like the sarcoma variant, these tumors also present with a large mass in the abdomen and abdominal discomfort. Association with human papillomavirus appears to be the most common factor that gives rise to squamous histology.

CONCLUSION

Retroperitoneal SCC is an uncommonly diagnosed entity. Although no specific treatment guidelines exist for this uncommon malignancy; surgery followed by adjuvant or definitive radiotherapy with concurrent chemotherapy (in inoperable cases) seems a feasible option. Multicentre trials should be conducted for establishing definitive treatment strategies for this ailment.

Clinical application of real-time PET/CT guided targeted retroperitoneal masses biopsy in diagnosing malignant tumors

OBJECTIVE

To explore the feasibility, safety, and clinical application value based on the fusion image of 18 F-FDG PET/CT, for guiding retroperitoneal puncture biopsy technology and to determine the diagnosis of retroperitoneal masses in diagnosing malignant tumors.

METHODS

From March 2019 to January 2023, 42 patients underwent 18 F-FDG PET/CT imaging and were found to have retroperitoneal lesions that required definite diagnosis; 22 were male, 20 were female, and the average age was(59.17 ± 13.23) years. According to the fused 18 F-FDG PET/CT tomographic image, the target point with the highest metabolic activity, the safest, and expected maximum sample size was selected. CT scans were acquired with the same machine and fused with 18 F-FDG PET, guiding the puncture biopsy needle to approach the expected target zone, enabling timely delivery of pathological and immunohistochemical examination of the biopsy. Success rate, total examination time, biopsy operation time, complications, CT radiation dose, pathological, and immunohistochemical results were recorded.

RESULTS

All 42 patients were sampled successfully with the successful rate being 100%. The site of sampling of 42 patients accurately targeted the highest metabolic activity, the safest, and the expected maximum sample size. All 42 patients received clear diagnosis (25 cases of malignant tumors and cases of 17 benign tissues). 15 cases of patients had a change in clinical diagnosis, accounting for 35.7% of all patients, and affecting subsequent treatment plans. The average total examination time for patients was (41.3 ± 7.3) minutes, and the biopsy operation time was (29.1 ± 8.7) minutes. The effective radiation dose generated by the entire examination generated by CT guidance was (2.0 ± 0.5) mSv; no severe complications occurred in the patients.

CONCLUSION

Real-time-guided retroperitoneal puncture biopsy based on 18 F-FDG PET/CT fusion image is safe, accurate, and feasible, and can provide patients of retroperitoneal mass with clear pathological diagnosis and immunohistochemical evaluation.

Cystic retroperitoneal dedifferentiated liposarcoma: A case report

Liposarcoma is the most common primary retroperitoneal sarcoma in adults. We report the case of an 86-year-old male who presented to the emergency department with frequent falls and unexplained weight loss that was found to have a cystic retroperitoneal dedifferentiated liposarcoma. Initial computed tomography revealed a large heterogeneous complex cystic hypoenhancing lesion in the left retroperitoneum. Subsequent magnetic resonance imaging demonstrates a multilocular cystic mass with microscopic lipid content, diffusion restriction, and enhancing nodular soft-tissue components. Histologic examination of the tissue sample following biopsy is consistent with cystic retroperitoneal dedifferentiated liposarcoma. Further management was not pursued due to the patient's advanced age and frailty.

Primary neuroendocrine tumor in the retroperitoneal cavity: A rare case report

INTRODUCTION AND IMPORTANCE

Neuroendocrine tumors (NETs) are rare malignancies, accounting for a small percentage of gastrointestinal and bronchopulmonary cancers. Retroperitoneal NETs are infrequent and can be primary or metastatic. They are commonly metastatic rather than primary tumors, with primary retroperitoneal NETs being exceptionally rare.

CASE PRESENTATION

A 38-year-old woman presented with left flank pain persisting for one year, which had progressively worsened. Imaging revealed a large retroperitoneal mass exerting pressure on the stomach, spleen, liver, and upper pole of the left kidney. A biopsy of the tumor was done and the results were consistent with NET. The tumor, which measured approximately 19 × 12.5 × 11 cm, was surgically removed, and the pathological findings were consistent with the results of the biopsy prior to the surgery.

CLINICAL DISCUSSION

Neuroendocrine tumors are rare and exhibit diverse characteristics based on location, size, hormone secretion, and metastasis. Retroperitoneal neuroendocrine tumors are typically metastatic and rarely primary. The extremely large size of the tumor in this case highlights the surgical challenges associated with retroperitoneal NETs. Imaging, such as CT and MRI, plays a crucial role in diagnosis.

CONCLUSION

The study emphasizes the need to consider primary NETs as a possible cause of large retroperitoneal masses, especially if the tumor size is significant. Surgical resection is the primary treatment option with generally favorable outcomes. However, the size of the tumor can complicate treatment, and further research is needed to evaluate the effectiveness of postoperative adjuvant therapy and develop therapeutic approaches for recurrent NETs.

Imaging of Ganglioneuroma: A Literature Review and a Rare Case of Cystic Presentation in an Adolescent Girl

Retroperitoneal ganglioneuroma is a rare neuroectodermal tumor with a benign nature. We performed a literature review among 338 studies. We included 9 studies, whose patients underwent CT and/or MRI to characterize a retroperitoneal mass, which was confirmed to be a ganglioneuroma by histologic exam. The most common features of ganglioneuroma are considered to be a solid nature, oval/lobulated shape, and regular margins. The ganglioneuroma shows a progressive late enhancement on CT. On MRI it appears as a hypointense mass in T1W images and with a heterogeneous high-intensity in T2W. The MRI-"whorled sign" is described in the reviewed studies in about 80% of patients. The MRI characterization of a primitive retroperitoneal cystic mass should not exclude a cystic evolution from solid masses, and in the case of paravertebral location, the differential diagnosis algorithm should include the hypothesis of ganglioneuroma. In our case, the MRI features could have oriented towards a neurogenic nature, however, the predominantly cystic-fluid aspect and the considerable longitudinal non-invasive extension between retroperitoneal structures, misled us to a lymphatic malformation. In the literature, it is reported that the cystic presentation can be due to a degeneration of a well-known solid form while maintaining a benign character: the distinguishing malignity character is the revelation of immature cells on histological examination.

Differentiation of retroperitoneal paragangliomas and schwannomas based on computed tomography radiomics

The purpose of this study was to differentiate the retroperitoneal paragangliomas and schwannomas using computed tomography (CT) radiomics. This study included 112 patients from two centers who pathologically confirmed retroperitoneal pheochromocytomas and schwannomas and underwent preoperative CT examinations. Radiomics features of the entire primary tumor were extracted from non-contrast enhancement (NC), arterial phase (AP) and venous phase (VP) CT images. The least absolute shrinkage and selection operator method was used to screen out key radiomics signatures. Radiomics, clinical and clinical-radiomics combined models were built to differentiate the retroperitoneal paragangliomas and schwannomas. Model performance and clinical usefulness were evaluated by receiver operating characteristic curve, calibration curve and decision curve. In addition, we compared the diagnostic accuracy of radiomics, clinical and clinical-radiomics combined models with radiologists for pheochromocytomas and schwannomas in the same set of data. Three NC, 4 AP, and 3 VP radiomics features were retained as the final radiomics signatures for differentiating the paragangliomas and schwannomas. The CT characteristics CT attenuation value of NC and the enhancement magnitude at AP and VP were found to be significantly different statistically (P < 0.05). The NC, AP, VP, Radiomics and clinical models had encouraging discriminative performance. The clinical-radiomics combined model that combined radiomics signatures and clinical characteristics showed excellent performance, with an area under curve (AUC) values were 0.984 (95% CI 0.952-1.000) in the training cohort, 0.955 (95% CI 0.864-1.000) in the internal validation cohort and 0.871 (95% CI 0.710-1.000) in the external validation cohort. The accuracy, sensitivity and specificity were 0.984, 0.970 and 1.000 in the training cohort, 0.960, 1.000 and 0.917 in the internal validation cohort and 0.917, 0.923 and 0.818 in the external validation cohort, respectively. Additionally, AP, VP, Radiomics, clinical and clinical-radiomics combined models had a higher diagnostic accuracy for pheochromocytomas and schwannomas than the two radiologists. Our study demonstrated the CT-based radiomics models has promising performance in differentiating the paragangliomas and schwannomas.

Pelvic soft tissue sarcomas

Pelvic soft tissue sarcomas (PSTS) are a rare, heterogeneous group of tumors. They have been usually analyzed with retroperitoneal sarcomas (RPS), but actually have key differences. Due to their unique anatomic location, symptomatic presentation of PSTS may be more common than RPS. Adequate imaging approach is paramount for guiding differential diagnosis, while preoperative biopsy is mandatory, especially when preoperative treatment may be considered as initial approach. The most frequent histologic subtype is leiomyosarcoma, which is different as expected in the retroperitoneum where liposarcoma is the commonest histology. Also solitary fibrous tumor is commonly diagnosed in the pelvis. Surgical approach for PSTS differs from that for RPS mainly due to anatomic relations. Similarly, in the lack of definite evidence from specific trials about neoadjuvant and adjuvant treatments, the anatomic constraints to obtain wide margins in the pelvis as well as the expected functional outcome in case of organ resections should be factored into decision for individualized treatment offer. Vascular and genitourinary involvement are frequent, as well as herniation through pelvic foramina. For these reasons a multidisciplinary surgical team should always be considered. Early referral of these patients to high-volume centers is critical and may impact on survival, given that optimal initial resection is a major predictor of curative treatment. International consensus on PSTS treatment is advocated, similarly to the recent efforts realized for RPS.

CT and MR Imaging of Retroperitoneal Sarcomas: A Practical Guide for the Radiologist

Primary retroperitoneal sarcomas (RPS) represent around 10-16% of all sarcomas, with liposarcomas and leiomyosarcomas being the most common subtypes. RPS have some peculiar characteristics, imaging appearances, worse prognosis, and complications compared to other locations of sarcoma. Commonly, RPS primarily present as large masses, progressively encasing adjacent structures, causing mass effect, and complications. RPS diagnosis is often challenging, and these tumors may be overlooked; however, failure to recognize RPS characteristics leads to a worse prognosis for the patients. Surgery is the only recognized curative treatment, but the anatomical constraints of the retroperitoneum limit the ability to achieve wide resection margins; therefore, these tumors have a high rate of recurrence, and require long-term follow-up. The radiologist has an important role in the diagnosis of RPS, the definition of their extent, and their follow-up. Specific knowledge of the main imaging findings is required to reach an early diagnosis, and, ultimately, to guarantee the best patient management. This article provides an overview of the current knowledge regarding cross-sectional imaging features of patients with retroperitoneal sarcomas, presenting tips and tricks to improve imaging diagnosis of RPS.

Retroperitoneal urothelial carcinoma arising after bladder diverticulectomy: a case report

BACKGROUND

Urothelial carcinoma arises from the inner urothelial membrane of the renal pelvis, ureter, and bladder and often causes macrohematuria. Here, we report a rare case in which the patient developed non-symptomatic urothelial carcinoma anatomically outside the bladder wall 17 years after bladder diverticulectomy.

CASE PRESENTATION

An 82-year-old male patient previously underwent gastrectomy for stomach cancer and partial hepatectomy for intrahepatic cholangiocarcinoma. Follow-up computed tomography revealed a tumor in the retroperitoneal space, where a bladder diverticulum was removed 17 years earlier. Multiparametric magnetic resonance imaging suggested that the tumor was malignant with rectal invasion. Subsequent computed tomography-guided percutaneous biopsy revealed that the tumor was urothelial carcinoma. The patient underwent two courses of neoadjuvant chemotherapy followed by pelvic exenteration with pelvic lymph node dissection. He is currently receiving adjuvant therapy with an immune checkpoint inhibitor and has had no recurrence for 3 months.

CONCLUSIONS

Multiparametric magnetic resonance imaging is a helpful tool for predicting both tumor malignancy and invasion before a pathologically confirmed diagnosis. Although this case is rare, urologists should be aware of the occurrence of urothelial carcinoma after bladder diverticulectomy in cases of incomplete resection of the diverticulum.

Retroperitoneal desmoid-type fibromatosis: a case report

Desmoid-type fibromatosis (DF) is a rare subtype of soft tissue sarcomas that most commonly occurs in the anterior abdominal wall. When occurring in the retroperitoneum, DF is usually part of familial syndromes while only rarely sporadic. This makes it imperative to report any instance of experience with DF and the oncological outcomes of the different approaches to management. We report two cases of sporadic and severe DF occurring in the retroperitoneum at our institution.

Case presentation

The first case is a male that presented with urinary obstruction symptoms and underwent surgical resection of the tumor that extended into the left kidney. The second case is a female with a history of recurrent desmoid tumors of the thigh and was incidentally diagnosed with retroperitoneal DF on imaging. She underwent tumor resection and radiotherapy; however, the tumor recurred with urinary obstruction symptoms that required another surgical resection. Histopathological characteristics and radiological imaging of both cases are described below.

Clinical discussion

Desmoid tumors often recur, thus significantly influencing the quality of life which is reflected in one of our cases. Surgery remains a mainstay treatment, and both cases presented in this report required surgical resection of the tumors as symptomatic and curative measures.

Conclusion

Retroperitoneal DF is a rare entity, and our cases add to the scarce literature available on the topic, which may well contribute to the formulation of practice-changing recommendations and guidelines focused on this rare variant of DF.

Safety and accuracy of aortic and periaortic CT-guided percutaneous core needle biopsy

PURPOSE

The purpose of this study was to determine the safety and accuracy of aortic and periaortic computed tomography (CT)-guided percutaneous core needle biopsy performed at a single center over 12 years.

MATERIALS AND METHODS

A retrospective review was conducted of cases performed between February 2010 and August 2022 in which the biopsied region was in direct contact with the aorta or great vessels including the pericardium and common iliac arteries. Clinical notes were reviewed for any early or delayed complications following the procedure, which if present were graded using the National Institute of Health's Common Terminology Criteria for Adverse Events, version 5.0. Pathology results were compared to subsequent outside biopsy results or follow-up surgical pathology, if available, as well as subsequent clinical decision making and/or clinical course, to determine concordance. Sensitivity, specificity, predictive value, and accuracy (indicative of diagnostic yield) were calculated.

RESULTS

32 core needle biopsies were reviewed from 30 patients (average lesion longest diameter 3.1 cm, range 0.5-10.9 cm; average needle proximity to the vessel endothelium or deep side of the pericardium 1.0 cm, range 0.3-1.8 cm). Complications occurred in 46.9% of cases (15/32), 93.3% (14/15) of which were minor and included small amounts of bleeding or pain. One patient developed a small nonemergent pneumothorax. Of biopsies obtained, 96.9% provided adequate tissue for diagnosis (31/32). When evaluating concordance between pathological and final diagnosis, sensitivity was 94.7% and specificity was 83.3%; positive and negative predictive value were 90.0% and 90.9%, respectively. Accuracy (diagnostic yield) of biopsy was 90.3%.

CONCLUSION

CT-guided percutaneous aortic and periaortic core needle biopsies are safe and efficacious procedures with high diagnostic yield.

Review of diagnosis, differential diagnosis, and management of retroperitoneal lymphangioma

Lymphatic malformation (LM) is the currently preferred term for what was previously known as lymphangioma. Retroperitoneal LMs are extremely rare, benign, cystic masses that arise from lymphatic vessels. They can be challenging to diagnose because they resemble other retroperitoneal cystic tumors. The development of treatment strategies for rare diseases, including retroperitoneal LM, requires the acquisition of new knowledge to enhance our understanding of the disease progression. Therefore, we present an update regarding fundamental and advanced issues associated with retroperitoneal LM. This review describes the epidemiology, histopathology, biomedicine, clinical manifestations, radiological features, differential diagnosis, and management of this lesion.

Extramedullary Hematopoiesis: A Forgotten Diagnosis and a Great Mimicker of Malignancy

ABSTRACT

Radiology errors have been reported in up to 30% of cases when patients have abnormal imaging findings. Although more than half of errors are failures to detect critical findings, over 40% of errors are when findings are recognized but the correct diagnosis or interpretation is not made. One common source of error is when imaging findings from one process simulate imaging findings from another process but the correct diagnosis is not made. This can result in additional imaging studies, unnecessary biopsies, or surgery. Extramedullary hematopoiesis is one of those uncommon disease processes that can produce many imaging findings that may lead to misdiagnosis. The objective of this article is to review the common and uncommon imaging features of extramedullary hematopoiesis while presenting a series of interesting relevant illustrative cases with emphasis on CT.

[A CASE OF PERIVESICAL ABSCESS CAUSED BY MIGRATION OF A FOREIGN BODY FROM THE INTESTINAL TRACT]

A 76-year-old woman was referred to our department because of high fever and bladder irritative symptoms. Computed tomography revealed the presence of a heterogeneous mass with indistinct borders on the left anterior wall of the bladder. The lesion contained a linear hyperdense shadow. We initially suspected malignancy, such as urachal carcinoma or soft-tissue sarcoma. However, upon review of previous computed tomography scans, it was confirmed that the linear hyperdense shadow had migrated from the intestinal tract to the bladder. Considering the possibility of abscess formation caused by a foreign body, we decided to perform a transurethral biopsy. The results of the pathological analysis showed abscess formation. The patient was diagnosed with perivesical abscess caused by accidental ingestion of a fish bone. Following the administration of antibiotics, the lesion markedly shrank. Although it is difficult to distinguish perivesical abscess from malignant disease, invasive treatment can be avoided by appropriate diagnosis based on imaging studies.

Primary retroperitoneal hydatid cyst, a rare novel differential diagnosis of retroperitoneal masses: A case report

The presence of primary retroperitoneal hydatid cysts is rare, even in endemic areas. The authors report a young man with a retroperitoneal hydatid cyst who underwent total cystectomy. The surgeons should suspect hydatid cysts in case of any abdominal cysts, especially in endemic areas, and avoid any spillage and puncture.

Pediatric mediastinal masses

Mediastinal masses are categorized based on the International Thymic Malignancy Interest Group (ITMIG) classification into prevascular, visceral and paravertebral compartments. The schema is based on cross-sectional imaging, mainly CT, and helps with generating a differential diagnosis based on location of the mass. Up to half of all pediatric mediastinal tumors are malignant. In this review we describe mediastinal masses that are relevant to the pediatric population, as well as the role of MR imaging of mediastinal masses and its advantages.

The Role of CT in the Staging and Follow-Up of Testicular Tumors: Baseline, Recurrence and Pitfalls

Ultrasound imaging of the testis represents the standard-of-care initial imaging for the diagnosis of TGCT, whereas computed tomography (CT) plays an integral role in the initial accurate disease staging (organ-confined, regional lymph nodes, or sites of distant metastases), in monitoring the response to therapy in patients who initially present with non-confined disease, in planning surgical approaches for residual masses, in conducting follow-up surveillance and in determining the extent of recurrence in patients who relapse after treatment completion. CT imaging has also an important place in diagnosing complications of treatments. The aims of this article are to review these different roles of CT in primary TGCT and focus on different pitfalls that radiologists need to be aware of.

A case report of mesenteric involvement in neurofibromatosis type 1

Mutations in the Neurofibromatosis Type 1 (NF-1) gene, which is located on chromosome 17q11.2, are the cause of NF-1, an autosomal dominant hereditary condition in which tumors of the nerve system develop. Neurological, skeletal, and cutaneous abnormalities are symptoms of the condition. Of all gastrointestinal tract lesions, mesentery lesions are the least common. There are many gastrointestinal problems that can accompany mesenteric neurofibromas, or they may not. We describe a case of a 5-year-old kid with mesenteric neurofibromatosis, which results in bowel obstruction and abdominal discomfort. On a CT scan, the mesenteric vasculature was completely encircled by homogenous soft tissue lesions without any vessel wall invasion. Diffuse mesentery lesions were discovered during surgery, although they could not be fully removed.

Solid Primary Retroperitoneal Masses in Adults: An Imaging Approach

Mass lesions in the retroperitoneal space may be primary or secondary. Primary retroperitoneal mass lesions are relatively uncommon as compared to pathology that arises secondarily from retroperitoneal organs. These may be solid or cystic lesions. The overlapping imaging features of various solid primary retroperitoneal tumors make the diagnosis difficult, and hence, histopathology remains the mainstay of diagnosis. This paper provides a brief review of the anatomy of the retroperitoneal space and provides an algorithmic approach based on cross-sectional imaging techniques to narrow down the differential diagnosis of solid primary retroperitoneal masses encountered in the adult population.

Pancreaticoduodenal Groove: Spectrum of Disease and Imaging Features

The pancreaticoduodenal groove (PDG) is a small space between the pancreatic head and duodenum where vital interactions between multiple organs and physiologic processes take place. Muscles, nerves, and hormones perform a coordinated dance, allowing bile and pancreatic enzymes to aid in digestion and absorption of critical nutrition. Given the multitude of organs and cells working together, a variety of benign and malignant entities can arise in or adjacent to this space. Management of lesions in this region is also complex and can involve observation, endoscopic resection, or challenging surgeries such as the Whipple procedure. The radiologist plays an important role in evaluation of abnormalities involving the PDG. While CT is usually the first-line examination for evaluation of this complex region, MRI offers complementary information. Although features of abnormalities involving the PDG can often overlap, understanding the characteristic imaging and pathologic features generally allows categorization of disease entities based on the suspected organ of origin and the presence of ancillary features. The goal of the authors is to provide radiologists with a conceptual approach to entities implicating the PDG to increase the accuracy of diagnosis and assist in appropriate management or presurgical planning. They briefly discuss the anatomy of the PDG, followed by a more in-depth presentation of the features of disease categories. A table summarizing the entities that occur in this region by underlying cause and anatomic location is provided. ^©RSNA, 2022.

A desmoid-type fibromatosis in the retroperitoneum of the gastro-pancreatic region that was resected with a distal pancreatomy: a case report

An 80-year-old man was referred to our hospital because of epigastric pain. Abdominal computed tomography revealed a well-defined circular intra-abdominal mass in the gastro-pancreatic region measuring 15 mm in diameter. After 6 months, the mass lesion was growing with mild enhancement, and weaker enhancement was found in the lower half of the mass on contrast-enhanced computed tomography. The mass lesion touched the stomach, whereas adipose tissue appeared to intervene between the mass and pancreas. On magnetic resonance imaging, the well-defined mass lesion had isointensity to muscle on T1-weighted imaging, slight hyperintensity to muscle on T2-weighted imaging, which indicated a rich fibrous tumor. Under general anesthesia, the patient underwent open surgery. Intraoperatively, the tumor was separated from the stomach and firmly attached to the pancreas. Therefore, we performed a distal pancreatomy with splenic resection. Pathological diagnosis was desmoid-type fibromatosis in the retroperitoneum, and the tumor margin was attached to the pancreas, splenic artery, and splenic vein. Since there are few reports of desmoid-type fibromatosis occurring in the retroperitoneum of the gastropancreatic region, it is difficult to distinguish from other soft tissue tumors and to identify the tumor origin. Close observation by radiological re-valuation was a useful option. Magnetic resonance imaging signals and an enhanced pattern may help distinguish a desmoid-type fibromatosis from other soft tissue tumors. A desmoid-type fibromatosis that is well-defined in radiological findings may infiltrate the surrounding organs with gross or pathological analyses.

Neuroendocrine Neoplasms of the Female Genitourinary Tract: A Comprehensive Overview

Simple Summary

Primary neuroendocrine neoplasms (NENs) are a rare, heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. NENs in the urinary tract are observed in <0.05% of individuals, in whom the bladder is the most common site. In this review, we described the epidemiology, pathogenesis, imaging, staging, and management of the genitourinary NENs.

Abstract

Primary neuroendocrine neoplasms are a rare heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. An extensive literature search was used to compile the data regarding epidemiology, pathogenesis, imaging features, and management of the urinary system NENs. We also included the updated staging of the NENs at various locations of the urinary system.

Robotic-assisted resection of pelvic mesorectum lipoma during the COVID-19 pandemic: a case report

Mesorectal lipoma is a rare, usually asymptomatic tumor. The best treatment is R0 resection but the previous literature reports different approaches. Robotic surgery allows for an accurate intervention, with a faster postoperative course, less risk of infection and need for transfusions, a faster return to normal daily activities and the best esthetic result. We describe a case of a 43-year-old female with a large lipoma with dislocation of the vagina, rectum and distal sigmoid colon, potentially malignant, successfully treated by robotic excision, which was safe, effective and well tolerated by the patient.

Schwannoma in and around the porta hepatis: radiological features in eight cases and literature review

PURPOSE

Schwannomas in and around the porta hepatis (porta hepatic schwannomas) are rare benign tumors easily misdiagnosed as other pathologies, including malignancies. We aimed to evaluate their imaging features on ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT).

METHODS

We performed a multi-institutional retrospective study by reviewing the clinical and imaging findings of pathologically proven eight porta hepatic schwannomas (mean age, 55 years; range, 38-80 years; one male and seven females). Preoperative imaging included three ultrasonography, eight CT, eight MRI, and two FDG-PET/CT.

RESULTS

All patients were asymptomatic. The mean tumor size was 61.9 mm (range, 30-180 mm), and all tumors demonstrated well-defined lesions on ultrasonography and their solid components showed soft tissue attenuation on non-contrast CT. MRI showed two distinct components in all cases: the component with T1-weighted hypointensities and T2-weighted hyperintensities with poor enhancement (suggestive of Antoni B histology); the component with T2-weighted hypointensities with gradually increasing enhancement (suggestive of Antoni A histology), resulting in a heterogeneous pattern on post-contrast CT or MRI (8/8, 100%). The separated deviation of surrounding bile ducts and vessels without obstruction allowed the recognition of extrahepatic localization and their benign nature. A ginger root-like morphology (2/8, 25%) seemed to be suggestive of extension along the Glisson's sheath, although this finding was not seen frequently.

CONCLUSION

Recognizing imaging features such as extrahepatic location, benign nature with internal structures suggestive of Antoni A/B histology, and characteristic tumor extension may provide key diagnostic clues for porta hepatic schwannomas.

Treatment of a Double Cancer Patient With Primary Inferior Vena Cava Sarcoma and Lung Adenocarcinoma: A Case Report and Literature Review

Background

Leiomyosarcoma of the inferior vena cava (IVC) is a rare malignancy. Here, we present the case of a 38-year-old woman with a primary IVC leiomyosarcoma and lung adenocarcinoma.

Case Report

The patient, a 38-year-old Chinese female, presented to the general surgical outpatients clinic with a 18-month history of intermittent right upper abdominal pain. Contrast-enhanced computed tomography (CT) showed a tumor of IVC (3.4^*2.7 cm) extending to the renal veins. In addition, chest CT revealed a mass lesion in the upper left lung lobe. Then, the patient underwent resection of the IVC tumor and wedge resection of the upper lobe of the left lung. The patient then received gefitinib (250 mg/day) as a maintenance therapy until the tumor recurrence or metastasis in the follow-up period. Pulmonary metastasis of the sarcoma were first diagnosed 20 month after the resection of the IVC leiomyosarcoma. So the patient again received thoracoscopic wedge pneumonectomy, and it was confirmed to be metastasis of IVC leiomyosarcoma. The patient received oral anlotinib treatment (12 mg once daily) after the last operation. During on-going regular follow-up visits no evidence of recurrence or metastasis was observed from December 2020 to October 2021.

Conclusions

The patient with a primary IVC leiomyosarcoma and lung adenocarcinoma is extremely rare. Surgery is still an effective treatment for patients with a primary IVC leiomyosarcoma and lung adenocarcinoma at present.

Imaging findings of spontaneous intraabdominal hemorrhage: neoplastic and non-neoplastic causes

Contrary to traumatic and iatrogenic intraabdominal hemorrhages, spontaneous intraabdominal hemorrhage is a challenging clinical situation. A variety of neoplastic and non-neoplastic conditions may cause spontaneous intraabdominal bleeding. Imaging findings vary depending on the source of bleeding and the underlying cause. In this article, we aim to increase the awareness of imagers to the most common causes of spontaneous intraabdominal hemorrhage by using representative cases.

Three cases of retroperitoneal sarcoma in which bioabsorbable spacers (bioabsorbable polyglycolic acid spacers) were inserted prior to carbon ion radiotherapy

From August 2019 to August 2020, we inserted polyglycolic acid (PGA) spacers and administered carbon ion radiotherapy (CIRT) to three cases of retroperitoneal sarcoma at our hospital. We aimed to investigate its utility and safety for retroperitoneal sarcoma. We analyzed changes in PGA spacer volume and corresponding computed tomography (CT) values in addition to the dose distribution using in-room CT images that were obtained during treatment. We assessed adverse events and investigated the suitability, safety and effectivity of PGA spacer insertion. During treatment, changes in PGA spacer volumes and CT values were confirmed. Volumes increased in patients with a folded PGA spacer, and it increased 1.6-fold by the end of irradiation compared with planning CT. The CT values decreased by 20-50 Hounsfield units at the end of irradiation compared to the planning CT. Dose distribution evaluation showed that the dose to the gastrointestinal tract adjacent to the tumor was maintained below the tolerable dose, and a sufficient dose was delivered to the target by PGA spacer insertion. One case of subileus caused during abdominal surgery for PGA spacer insertion occurred. No other adverse events, such as digestive disorders, were observed. CIRT with PGA spacer insertion for retroperitoneal sarcomas is safe and effective. For cases in which there is no option but to perform irradiation using a PGA spacer, precautionary measures such as verification of dose distributions using CT images are necessary.

Mimics and Pitfalls of Primary Ovarian Malignancy Imaging

The complex anatomy and similarity of imaging features of various pathologies in the pelvis can make accurate radiology interpretation difficult. While prompt recognition of ovarian cancer remains essential, awareness of processes that mimic ovarian tumors can avoid potential misdiagnosis and unnecessary surgery. This article details the female pelvic anatomy and highlights relevant imaging features that mimic extra-ovarian tumors, to help the radiologists accurately build a differential diagnosis of a lesion occupying the adnexa.

Unclear retroperitoneal tumors, an interdisciplinary challenge - A case report and review of the literature

INTRODUCTION AND IMPORTANCE

Unclear retroperitoneal tumors impose major challenges for clinicians. Tumors can originate primarily from retroperitoneal tissue or secondarily invade into the retroperitoneum. While benign lesions also occur, malignant tumors are far more common. Clinical presentation depends on replacement or invasion of other organs and is therefore highly variable. The heterogeneous tumor composition makes a definitive preoperative diagnosis difficult. Surgical resection is the gold standard for treatment but often proves challenging due to frequent involvement of large retroperitoneal vessels.

CASE PRESENTATION

We present the case of a 70-year old woman diagnosed with a large, unclear retroperitoneal tumor. Initial clinical symptoms were increasing dyspnea and dysphagia in our clinic. Gastroenterologic and cardiologic workup was unremarkable. Computed Tomography (CT) revealed a large retroperitoneal mass in the right upper abdomen with severe displacement of the inferior vena cava and renal veins. The patient was scheduled for primary tumor resection. The procedure was challenging due to the vessel involvement and large blood pressure alterations during tumor mobilization. The post-op pathologic workup then revealed the rare finding of a completely resected paraganglioma. The post-surgical course was uneventful. One year after diagnosis, the patient is relapse-free.

CLINICAL DISCUSSION

Among retroperitoneal tumors, paragangliomas and pheochromocytomas are rare tumor entities. Asymptomatic, sporadic disease is hard to identify preoperatively and can cause unexpected complications in the OR. An experienced team is crucial in achieving best short- and long-term outcomes.

CONCLUSION

This case impressively shows the challenges of retroperitoneal tumors and the importance of interdisciplinary work in these cases.

Ultrasound and alternative multimodality imaging of intra-abdominal and pelvic cystic masses in the newborn

Introduction: Ultrasound is used commonly to detect and diagnose intra-abdominal and pelvic cystic masses in the newborn as it is easily available, relatively low cost, and non-invasive. Discussion: The diagnosis can be made or narrowed down by determining the location, size, sonographic features, organ involvement, and internal vascularity. The differential diagnoses include hydronephrosis, multicystic dysplastic kidney, adrenal haemorrhage, cystic teratomas, ovarian cysts, enteric cysts, meconium cysts, and liver haemangiomas. With the appropriate radiological knowledge, the ultrasound practitioner can help obtain an accurate diagnosis. Conclusion: This pictorial essay will familiarise the reader with the different common causes of intra-abdominal and pelvic masses detected on ultrasound through a wide range of conditions. The role of ultrasound in the evaluation of these conditions will be discussed and alternative imaging correlates will be offered.

Extensive abdominal lymphangiomatosis involving the small bowel mesentery: A case report

BACKGROUND

Abdominal lymphangiomatosis is a rare benign condition accounting for less than 1% of all the cases of lymphangiomatosis. Management usually involves radical surgical excision; however, depending upon the extent of involvement, patient condition, and absence of complications, conservative management can be also considered.

CASE SUMMARY

We present the case of a 32-year-old male who presented with short onset abdominal pain and melena. Physical examination findings were within normal limits, except for left lower abdominal tenderness. Upper gastrointestinal endoscopy was within normal limits. Abdominal and pelvic ultrasound and computed tomography (CT) scan revealed numerous, variably-sized cystic lesions within the abdominal cavity, exclusively and extensively affecting the small bowel mesentery with sparing of the retroperitoneum. The diagnosis was confirmed by CT and cytological examination. Radical surgical excision was technically impossible in this patient because of the extensive involvement of the mesentery; therefore, the patient was managed conservatively.

CONCLUSION

Extensive and exclusive small bowel mesentery involvement in abdominal lymphangiomatosis is rare. Imaging modalities play an important role in establishing the diagnosis and conservative management can be considered when surgery is technically impossible.

Pancreatic/peripancreatic neurogenic tumor; little known masses not to be missed

BACKGROUND

Retroperitoneal neurogenic tumors are extremely rare pathological entities; therefore, few clinical features and natural courses, especially originating from the pancreatic/peripancreatic regions, have been reported. This study aimed to investigate the clinicopathological features of pancreatic and peripancreatic neurogenic tumors and assess the diagnostic value of computed tomography (CT) and endoscopic ultrasound-guided fine needle biopsy (EUS-FNB).

METHODS

Between 2006 and 2018, patients who were diagnosed with neurogenic tumors were included. In total, 90 histologically confirmed cases of neurogenic tumors located in the pancreatic/peripancreatic regions were selected for analysis.

RESULTS

The mean age was 49.2 ± 13.1 years. There were no differences in sex distribution of the tumors. Schwannomas (44.4%) and paragangliomas (41.1%) were the most common neurogenic tumors. The sensitivity of CT was 62.2% in 90 cases. EUS-FNB was performed in 30 cases and the sensitivity of it was 83.3%. The diagnosis of neurogenic tumors with EUS-FNB or CT was not significantly associated with tumor location and size. Surgical resection was performed in 78 cases. Of the 12 patients who did not undergo surgery, 10 cases were followed-up without any increase in tumor size.

CONCLUSIONS

Through the present study, we verified radiological, pathological, and clinical aspects of the pancreatic/peripancreatic neurogenic tumors which little known before, therefore, this study can serve as the basis for research to present an optimal diagnosis and treatment of neurogenic tumors. In addition, EUS-FNB is useful in the diagnosis of pancreatic/peripancreatic neurogenic tumors with relatively high sensitivity and can help establish therapeutic plans before the surgery.

Retroperitoneal lymphangioma mimicking malignant tumor treated by pancreaticoduodenectomy

Lymphangiomas are classified as lymphatic malformations, which are more common in children and rare in adults. It frequently occurs in the cervical and axillary regions and uncommonly in the retroperitoneum. A 39-year-old woman presented to our department for the investigation for a 55 mm asymptomatic mass in the right anterior adrenal cavity. Abdominal ultrasound showed a tumor containing cysts in the right anterior adrenal cavity. Contrast-enhanced computed tomography showed that the tumor was poorly contrasted and ill-defined. Magnetic resonance imaging suggested that the tumor contained a small amount of fat. The tumor tended to grow, and the possibility of malignant diseases such as liposarcoma could not be excluded. Therefore, surgical resection was performed. Since intraoperative findings showed that the tumor tightly invaded to the duodenum and pancreatic head, a pancreaticoduodenectomy was selected. The entire tumor was removed without exposing the tumor. Macroscopic findings indicated that the specimen was 55 mm in size, indistinctly demarcated, yellow-white in color, and polycystic. Histologically, lymphovascular proliferation was observed with infiltration of the pancreatic head and the duodenal muscle layer. The diagnosis of lymphangioma was finally made. There was no recurrence 2 years after surgery.

Abscess or Tumor? When a Retroperitoneal Mass on Computerized Tomography Turns Out to Be a Rare Soft Tissue Growth

A retroperitoneal finding on a computerized tomography scan, in a symptomatic patient, can harbor the clinician to many differential diagnoses from infectious to malignancy. Desmoid fibromatosis (DF), a relatively innocuous mass that can spread locally, can be found in that anatomical region. Even for a rare tumor such as DF, our patient did not meet the usual benchmarks of this cancer, being an elderly female and having it appear as an abscess radiologically. Timely clinical response with radiotherapy and tamoxifen allowed our patient's DF to regress and resolved her symptoms.

Radiologic-Pathologic Correlation of Primary Retroperitoneal Neoplasms

An earlier incorrect version of this article appeared in print. The online version is correct.

Potential application value of PET/computed tomography in retroperitoneal leiomyosarcoma and a literature review

OBJECTIVE

To analyze the fluorine-18 fludeoxyglucose PET/computed tomography (18F-FDG PET/CT) findings of retroperitoneal leiomyosarcoma (RLMS) and the role of this method in differentiating between benign and malignant masses and classifying the malignant degree to improve the understanding of this rare disease.

METHODS

Eight leiomyomas (A group), 13 RLMSs (B group), and 20 postoperative recurrence/metastasis RLMSs (C group) were enrolled. PET/CT features of B group were analyzed. The differences of metabolic parameters between three groups were compared, receiver operating characteristic (ROC) curve analysis was performed to group A and B, and correlation analysis was performed to subgroup B.

RESULTS

(1) The RLMS patients were more likely to be female, and PET/CT showed a high degree of heterogeneous metabolism in the soft tissue mass. (2) The standardized uptake value (SUV) of RLMS were significantly higher than those of benign leiomyomas (P < 0.05). The area under the ROC curve was 0.909, the sensitivity and specificity for diagnosing RLMS were 0.923 and 0.750, respectively, The SUVmax and SUVstd of primary RLMS were moderately associated with the Ki67 index. The mean SUVmax in the G1, G2 and G3 subgroups increased successively (4.15 ± 0.35, 6.47 ± 0.83, and 10.13 ± 4.29, respectively). (3) Primary RLMS was characterized by local invasion, but hematogenous metastasis and lymph node metastasis were rare. Postoperative recurrence/metastasis of RLMS was characterized by local recurrence and hematogenous metastasis, but lymph node metastasis was rare.

CONCLUSION

PET/CT has potential value in the preoperative staging, benign and malignant differentiation, malignant degree classification and postoperative follow-up of RLMS.

Large retroperitoneal leiomyoma developed from the pelvic floor to the buttocks

Retroperitoneal leiomyoma is a very rare disease, with little reported information on its origin. Herein, we report a case of a large retroperitoneal leiomyoma that developed from the pelvic floor. A 44-year-old woman had a large mass protruding outside the body from the right hip. Imaging revealed a large tumor developing from the pelvic floor to the buttocks. It was difficult to identify the place of origin. Upon preoperative biopsy, the patient was diagnosed with retroperitoneal leiomyoma. Tumor removal with abdominoperineal and partial vaginal resection was performed. Based on the histological findings of the surgical specimens, she was diagnosed with a retroperitoneal leiomyoma (gynecologic type) via immunohistochemistry, the tumor cells were positive for αSMA, desmin, estrogen receptor(ER), and progesterone receptor(PgR), but negative for myoglobin, S-100, CD34, and MIB-1.This is a case of a large retroperitoneal leiomyoma that was successfully removed via abdominoperineal and partial vaginal resection.

Extensive mature cystic teratoma in the pelvis of an adult male patient mimicking a prostatic abscess

Mature cystic teratomas are rare neoplasms composed of tissues from at least two of the germ layers. In the adult male pelvis, these tumors are exceptionally rare; only a small number of cases have been reported in the literature. We describe the case of a 76-year-old male with an extensive mature cystic teratoma in the rectovesical space, perineum, scrotum, and gluteal folds. This was misdiagnosed and managed as a chronic prostate abscess for six years. Few cases in the literature have reported mature cystic teratomas presenting as abscesses in male patients, and none in the male pelvis. This presentation should prompt physicians to consider the diagnosis of teratoma when managing similar cases, especially if cultures are negative and the symptoms recur despite treatment.

"Wrap-Around Sign" in Non-Hodgkin Lymphoma of the Spine: A Common yet Overlooked Imaging Feature?

BACKGROUND

Anecdotal cases of the so-called "wrap-around" appearance in non-Hodgkin lymphoma (NHL) of the spine exist in the medical literature. In this paper, we looked at the prevalence of this imaging feature in our institutional cases.

MATERIALS AND METHODS

We screened our institutional database for biopsy-proven NHL. Our inclusion criteria were the histologically confirmed diagnosis of NHL involving any vertebra, available magnetic resonance imaging of the affected site, and a positive wrap-around sign. Exclusion criteria included lymphoma cases without the wrap-around sign and/or histology other than NHL. We subdivided the cases into 3 groups: 1) lymphoma wrapped around the vertebral body; 2) the posterior elements alone; or 3) both the vertebral body and posterior elements.

RESULTS

Our search identified 147 cases of NHL in which a confirmatory biopsy at the primary tumor site was available. Of those, 23 cases fulfilled the inclusion criteria (16 men and 7 women with average age at diagnosis of 63.3 years), yielding prevalence of 15.6% in our series. Most commonly the lymphoma involved the vertebral body with or without some involvement of the posterior vertebral elements (n = 20, 86.9%), followed by posterior vertebral elements (n = 2, 8.7%). One remaining case (4.4%) had lymphoma involving the anterior vertebral body and posterior elements.

CONCLUSIONS

Findings of our pilot study indicated that the wrap-around sign in cases of NHL could be helpful diagnostically. This sign may be frequently under-recognized, leading to potential for a diagnostic dilemma on imaging. Larger studies are necessary to obtain more precise information about the prevalence of the wrap-around sign.