Imaging of uncommon retroperitoneal masses

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.

Pathological Discrepancy: Simple Mesenteric Cyst vs. Mesenteric Lymphangioma

Introduction

Both mesenteric cysts and cystic lymphangiomas are scarce and clinically and radiologically almost identical derivatives, but their histological structure is fundamentally different. Case Presentation. A 52-year-old woman was consulted by a surgeon for a derivative felt in her abdomen. The patient said she felt a growing derivative in the abdomen about a month ago. After consulting and testing, a sigmoid colon mesenteric cyst (13 cm × 11 cm × 10 cm) was found. Complete excision of the cyst within healthy tissues was performed through laparotomy. The surgery had no complications. The initial pathological answer was a simple mesothelial cyst (a rare histological finding). However, immunohistochemical tests were performed that showed that diagnosis was mesenteric cystic lymphangioma (ML). Cystic lymphangiomas that have a link to the mesentery have been described less than 200 times.

Conclusions

Final differential diagnosis between different cystic derivatives is possible only based on histopathological examinations. Mesenteric lymphangioma is most common at a very young age, but in rare cases, it also occurs in adults. All clinicians should increase their awareness of the disease.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Diagnostic approach to primary retroperitoneal pathologies: what the radiologist needs to know

Retroperitoneal soft tissue lesions represent a wide range of disease processes with overlapping imaging findings. Familiarity with the CT and MR characteristics of these conditions is important to guide clinical evaluation. We review the tissue types, characteristic clinical, demographic, and imaging features of retroperitoneal tumors and tumor-like non-neoplastic conditions with CT and MR correlation, including anatomic and imaging clues, and provide a diagnostic approach to aide the radiologist in making a specific diagnosis.

Treatment of retroperitoneal echinococcosis: the experience of a single center

Retroperitoneal echinococcosis (RE) is a rare condition that is associated with a high mortality and disability rate. It is associated with a high rate of misdiagnosis, a high risk of surgery, and is extremely difficult to manage. There is no uniform standard for determining the exact form of surgical method and the timing of surgery.This was a retrospective analysis of the characteristics and surgical management of patients diagnosed with RE in our hospital between 2012 and 2019.Between 2012 and 2019, 1257 cases of echinococcosis and 121 cases of RE were diagnosed in our hospital. Of these, 68 cases involved surgical treatment, 53 involved non-surgical treatment, and 12 cases were lost to follow-up (4 cases in the surgical group and 8 cases in the non-surgical group). Thus, 109 cases were followed-up. RE cases were divided according to different treatment methods into a radical resection group (Group A, 31 cases), a non-radical resection group (Group B, 37 cases), and a non-surgical group (Group C, 53 cases). We carried out a detailed analysis of the 109 cases experiencing surgical intervention with effective follow-up.Our analysis found that radical resection is the first line of treatment of RE, although non-radical surgery can benefit most patients. It is important to emphasize the importance of the first round of surgery, particularly in cases involving hepatic echinococcosis. If the lesion can be removed radically during the first round of surgery, then radical surgery should be performed.

Macronodular adrenal hyperplasia masquerading as an upper pole renal mass

Macronodular hyperplasia (MAH) of the adrenal gland is a rare disease usually presenting with Cushing Syndrome. Although usually readily apparent on imaging, an adrenal tumor in an asymptomatic patient may be mistaken for a renal tumor. We present a patient with combined macro- and micro-nodular adrenal hyperplasia masquerading as an upper pole renal mass. The patient underwent a robotic partial nephrectomy and partial adrenalectomy without complication.

Unusual Manifestation of Immunoglobulin G4-Related Disease Involving the Retroperitoneum: A Case Report

Immunoglobulin G4 (IgG4)-related disease is a systemic disease characterized by dense lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells and fibroblast proliferation. The retroperitoneal involvement of IgG4-related disease usually appears as a soft-tissue mass covering the abdominal aorta or entrapping the ureters, resulting in hydronephrosis. Here, we present a case of IgG4-related disease with retroperitoneal involvement in a 75-year-old woman with an unusual manifestation. A preoperative computed tomography (CT) scan revealed an irregular infiltrative retroperitoneal mass invading the normal anatomic barriers, raising the suspicion of malignancy or inflammation. Contrast-enhanced CT revealed a homogeneous progressive enhancement of the mass.

Imaging Features of Neurofibromatosis Type 1 in the Abdomen and Pelvis

OBJECTIVE. Loss of the neurofibromatosis type 1 (NF1) tumor suppressor protein causes uninhibited activation of the RAS oncogene, which leads to tumorigenesis in patients with NF1. This case-based review discusses imaging manifestations of NF1 in the abdomen and pelvis, highlighting key genetic associations and management to elucidate features different from the general population. CONCLUSION. The spectrum of pathologic findings includes gastrointestinal tumors such as gastrointestinal stromal tumors, genitourinary lesions including urogenital neurofibromas, vascular entities such as renal artery stenosis, and less common associations like lymphoma.

Burned-out testicular germ cell tumour presenting as acute inferior vena cava syndrome

Germ cell tumours (GCT) are the most common testicular neoplasms, seen mainly in young adults. Rarely they can affect extragonadal tissues, either as primary tumours or as metastases, most commonly to retroperitoneal lymph nodes. A 'burned-out' testicular tumour is a metastatic GCT with a relatively occult primary testicular tumour, which has histologically spontaneously regressed. We report a case of a 26-year-old man who presented with an acute history of lower back pain and leg swelling. CT demonstrated a large retroperitoneal soft tissue mass causing right-sided hydronephrosis with inferior vena cava and iliofemoral vein thrombosis. Although clinical examination of the testis was normal, ultrasound imaging of the scrotum identified a burned-out testicular primary. Orchiectomy confirmed the diagnosis and the patient responded well to chemotherapy, with no viable residual tumour on follow-up imaging. However, despite nephrostomy insertion, a dimercaptosuccinic acid (DMSA) scan demonstrated loss of function of the right kidney after treatment.

Intra-abdominal lymphangioma: A case report

Lymphangioma is a rare, benign congenital malformation of the lymphatic system that usually affects the neck and head in children. Intra-abdominal lymphangioma accounts for less than 5 percent of all cases of lymphangioma. The clinical presentation of intra-abdominal lymphangioma can vary from asymptomatic to nausea, vomiting, and abdominal pain. The diagnosis of intra-abdominal lymphangioma is based on imaging modalities and histopathological examination. The definitive treatment is surgical resection. Here we describe the interesting and rare case of a 29-year-old woman with lymphangioma of the retroperitoneum extending to the root of the mesentery. We focus on the diagnosis and management of this rare tumor by the application of radiological modalities and pathological analysis.

Effectiveness of gallium scintigraphy in diagnosing a spontaneous giant chronic expanding hematoma of the adrenal gland: A case report

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A chronic expanding hematoma of the adrenal gland is extremely rare.

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Chronic expanding hematomas mimic sarcomatous lesions.

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Gallium scintigraphy may help the differential diagnosis between chronic expanding hematomas and sarcomatous lesions.

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Complete resection of chronic expanding hematomas is the gold standard.

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Preoperative arterial embolization may reduce intraoperative bleeding on complete tumor removal.

Introduction

A chronic expanding hematoma in the retroperitoneal space is a rare disease with poorly understood pathology, and preoperative diagnosis of such hematomas using conventional methods is sometimes difficult.

Presentation of case

A 68-year-old man with a history of slowly progressive abdominal distention was referred to our department for further evaluation. Contrast-enhanced CT revealed a large retroperitoneal tumor of the adrenal gland. MRI revealed that the tumor was iso-intense to hyperintense on T2-weighted imaging, with heterogeneous signal intensity on T1-weighted imaging without fat components. Angiography of the left adrenal artery confirmed many extravasations into the tumor. However, gallium scintigraphy showed no accumulation in the tumor. These findings were suggestive of a chronic expanding hematoma of left adrenal gland. This patient underwent complete tumor resection. Postoperative histopathological findings revealed a chronic expanding hematoma.

Discussion

Chronic expanding hematomas are slowly expanding, space-occupying masses as a result of trauma, surgery, or bleeding disorders. Chronic expanding hematomas mimic malignant tumors such as sarcomatous lesions. Although CT and MRI are used to obtain the diagnosis, the diagnosis is sometimes difficult. Gallium scintigraphs play a pivotal role in the differential diagnosis between them.

Conclusion

Gallium scintigraphs, magnetic resonance imaging and computed tomography, are useful tools to differentiate chronic expanding hematomas from sarcomatous lesions.

Ovarian and non-ovarian teratomas: a wide spectrum of features

Teratoma is a germ cell tumor (GCT) derived from stem cells of the early embryo and the germ line. Teratoma is the most common neoplasm of the ovaries and is usually diagnosed easily using imagings by detecting fat components. However, there are various histopathological types and the imaging findings differ according to the type. Teratoma usually occurs in the gonads or in the midline due to migration of primordial germ cells during development. The clinical course of teratomas depends on the age of the patient, histological type, and anatomical site. Sometimes teratomas show unusual manifestations, such as mature teratoma without demonstrable fat components, torsion, rupture, growing teratoma syndrome, anti-N-methyl-D-aspartate receptor encephalitis, and autoimmune hemolytic anemia. For all of these reasons, teratomas demonstrate a wide spectrum of imaging features and radiologists should be familiar with these variabilities. The present article aims to introduce a model encompassing types of GCTs based on their developmental potential, and to review several histopathological types in various anatomical sites and unusual manifestations of teratomas, with representative imaging findings.

Leiomyosarcoma: a rare presentation as multifocal lesion

Leiomyosarcoma is a rare type of connective tissue cancer, accounting for 5–10% of all soft tissue sarcomas. We present a case of leiomyosarcoma as unusual multifocal presentation. Retroperitoneal, mediastinal, pulmonary, uterine and bony regions were all involved at the time of presentation. The liver was normal without detected lesions.

Retroperitoneal Sarcomas: An Update on the Diagnostic Pathology Approach

Retroperitoneal sarcomas are a heterogenous group of rare tumors arising in the retroperitoneum. Retroperitoneal sarcomas comprise approximately 10% of all soft tissue sarcomas. Though any soft tissue sarcoma histologic types may arise in the retroperitoneal space, liposarcoma (especially well-differentiated and dedifferentiated types) and leiomyosarcoma do so most commonly. Retroperitoneal sarcomas are diagnostically challenging, owing to their diversity and morphological overlap with other tumors arising in the retroperitoneum. An accurate diagnosis is necessary for correct management and prognostication. Herein, we provide an update on the diagnostic approach to retroperitoneal sarcomas and review their key histologic findings and differential diagnoses.

Benign adrenal and suprarenal retroperitoneal schwannomas can mimic aggressive adrenal malignancies: case report and review of the literature

The suprarenal retroperitoneum and adrenal gland is a rare site of origin for benign schwannomas which frequently present as larger and more aggressive lesions than schwannomas identified elsewhere. These tumors are often surgically excised. We present a case of an 81-year-old asymptomatic man presenting with an incidental 10 cm left suprarenal retroperitoneal mass identified on CT. The mass was indiscernible from the adrenal gland, demonstrating heterogeneous enhancement with a centrally cystic/necrotic core, and punctate calcifications. Subsequent core needle biopsy demonstrated a benign adrenal schwannoma. The lesion has been managed conservatively with imaging follow up and without complication. DISCUSSION: Our review of the literature identifies 121 reported in vivo benign adrenal and suprarenal schwannomas published to date with imaging features available for 90 cases (74%). All cases were encapsulated with the average size measuring over 6.5 cm. Fifteen percent (13/84) of reported lesions measured over 10 cm at presentation. Punctate calcification was present in 50% (26/52) of reporting cases. Nearly 50% (40/86) of cases demonstrate cystic/necrotic appearances on imaging. Despite aggressive appearances, our case demonstrates that biopsy and surveillance may represent a reasonable alternative to surgery in suboptimal surgical candidates.

The value of multiparameter 18F-FDG PET/CT imaging in differentiating retroperitoneal paragangliomas from unicentric Castleman disease

The aim of this study was to investigate the value of multiple parameters retrieved from the FDG PET/CT studies, including SUVmax, SUVmean, SUVpeak, MTV, TLG, tumour size in differentiating retroperitoneal paragangliomas from UCD. 28 patients with solitary retroperitoneal masses who had undergone preoperative 18F-FDG PET/CT were retrospectively evaluated. Histopathology by surgical resection confirmed 17 paragangliomas and 11 UCDs. SUVmax, SUVmean, SUVpeak, MTV, TLG, and tumour size of 18F-FDG PET/CT were measured for each patient. Mann-Whitney U-test was used to assess differences in multiple parameters between paragangliomas and UCDs. The ROC curve analysis was performed to determine the differential diagnostic value of these parameters. Paragangliomas presented significantly higher SUVmax (P < 0.001), SUVmean (P = 0.001), SUVpeak (P < 0.001), and TLG (P = 0.024) than UCDs, whereas no significant difference was observed in MTV. The AUCs for differentiating paragangliomas and UCDs were 0.920, 0.888, 0.909, and 0.765 for SUVmax, SUVmean, SUVpeak, and TLG, respectively. The SUVmax cut-off of 7.75 yielded 82.4% sensitivity and 100% specificity for predicting paragangliomas. This study indicated that 18F FDG PET/CT-derived multiple metabolic parameters are useful in distinguishing between paragangliomas and UCDs. SUVmax showed the best result for the differential diagnosis of these two diseases among multiple metabolic parameters.

Primary and secondary diseases of the perinephric space: an approach to imaging diagnosis with emphasis on MRI

The perinephric space is the middle compartment of the retroperitoneum, containing the kidneys and adrenal glands. Differential considerations for diseases involving primarily the perinephric space differ from those arising from the kidney itself, show variant imaging features, and require identification and characterisation by interpreting radiologists-an imaging diagnosis can be suggested in many cases. Lymphangiomas are congenital cystic lesions that may contain lipid-laden chyle, which may be detectable on magnetic resonance imaging (MRI). Retroperitoneal fibrosis, Erdheim-Chester disease, and lymphoma may present as a perinephric soft tissue rind. Osseous findings favour Erdheim-Chester, ureteric obstruction favours retroperitoneal fibrosis, and associated lymphadenopathy with mass-effect, but without invasion of adjacent structures favours lymphoma. Extramedullary haematopoiesis and brown fat stimulation are both characterised by signal drop on opposed-phase T1-weighted (W) images, the former resulting from severe anaemia and the latter in the context of elevated serum catecholamines, especially in the setting of phaeochromocytoma. Liposarcoma is the most common primary sarcoma of the retroperitoneum. Metastases are uncommon; however, they can be seen in melanoma, among other primary malignancies. Increased T1W signal hyperintensity is typical of melanoma metastases and haematomas. Abscesses show non-enhancing fluid centrally with marked diffusion restriction. This article presents a review of the perinephric space, pathological conditions of the perinephric space, and an approach towards imaging and diagnosis using cross-sectional imaging, with emphasis on MRI. MRI provides better tissue characterisation, assessment of enhancement kinetics, and detection of intralesional fat in comparison to CT. Clinical and laboratory correlation or tissue sampling may be required for definitive diagnosis in some cases.

A rare case of extraperitoneal gastrointestinal stromal tumor arising from kidney

Mesenchymal tumors of the gastrointestinal tract which arise from the interstitial cells of Cajal and express C-Kit protein or CD117 on immunohistochemistry are known as gastrointestinal stromal tumors (GISTs). Extraperitoneal GISTs (EGISTs) are rare tumors arising from the mesentery, omentum, or retroperitoneum. We report a case of a 52-year-old male who presented with a huge abdominal lump arising from the right renal capsule that was found to be EGIST on histopathological examination and immunohistochemistry.

Imaging features of adrenal gland masses in the pediatric population

The spectrum of adrenal masses in the pediatric population markedly differs from that in the adult population. Imaging plays a crucial role in detecting adrenal masses, differentiating malignant from benign lesions, recognizing extra-adrenal lesions in the suprarenal fossa, and directing further management. Ultrasound is the primary imaging modality of choice for the evaluation of adrenal masses in the neonatal period, whereas MRI or CT is used as a problem-solving tool. In older children, computed tomography or magnetic resonance imaging is often required after initial sonographic evaluation for further characterization of a lesion. Herein, we discuss the salient imaging features along with pathophysiology and clinical features of pediatric adrenal masses.

Non-adrenal tumors of the adrenal area; what are the pitfalls?

Discovery of an adrenal mass is nowadays a frequent situation. While adrenal tumors can cause a variety of symptoms, more often than not they are diagnosed incidentally on imaging exams such as CT-scan or MRI performed for another purpose. However, any retroperitoneal supra-renal mass can have an extra-adrenal origin. Indeed, operated non-adrenal masses initially but wrongly diagnosed as an adrenal disease represent about 3.5% of adrenalectomies. These differential diagnoses principally include retroperitoneal tumors that are malignant in two thirds of cases (lymphomas, sarcomas, neurogenic or germinal tumors), and more rarely vascular anomalies or congenital malformations, which are most frequently left-sided due to the wide variety of anatomical structures surrounding the left adrenal gland. Several lesions can originate from the adrenal gland or be located near the gland (paraganglioma, ganglioneuroma). Even though unilateral adrenalectomy is associated with low morbidity, ignorance of these differential diagnoses can cause ill-adapted management; overly conservative surgery in case of sarcoma is one example. Some of these lesions have characteristic clinical or imaging features (cystic lymphangioma, angiomyolipoma…). In other cases, assessment of hormonal secretion is required and additional exams (MRI, percutaneous biopsy, PET-scan with 18-Fluorodeoxyglucose) can correct an erroneous diagnosis. The above diagnostic approach allows appropriate management (with or without surgery). The purpose of this review was to highlight the main differential diagnoses of adrenal masses, to describe their characteristics, and to discuss their therapeutic management.

Comprehensive Review of Abdominopelvic Mesenchymal Tumors With Radiologic Pathologic Correlation and Update on Current Treatment Guidelines-Part 2

Soft-tissue sarcomas are a diverse group of rare mesenchymal malignancies accounting for only 1% of all solid adult malignancies. These have been categorized in 12 broad groups by the World Health Organization (WHO) with their recent update in 2013. Majority of them lack specific imaging features serving as imaging conundrums for a radiologist. These are often large masses at presentation as they are asymptomatic or cause vague clinical symptoms. These tumors are challenging for surgeons as well as they find it difficult to achieve complete resection because of complex intra-abdominal anatomy and their close relationship with critical structures. Often, a multidisciplinary approach is required to decide on the most appropriate management for these complex cases so as to provide optimal patient care. Knowledge of the WHO classification, pathologic features, and treatment options available helps the radiologist make a meaningful contribution in multidisciplinary discussions of such cases and overall patient care. Liposarcoma (well-differentiated and dedifferentiated liposarcomas), leiomyosarcoma, and gastrointestinal stromal tumor are the 3 most common primary intra-abdominal sarcomas. In part 1 of this article, general features of soft-tissue sarcomas and some of the common tumors from WHO category 1-4 found in abdomen and pelvis are discussed. Part 2 will focus on common tumors from remainder of the WHO categories.

Primary retroperitoneal germ cell tumor in an adult female: A case report

RATIONALE

Primary retroperitoneal germ cell tumors are uncommon and especially rare in female patients. However, this type should be included in the differential diagnosis of retroperitoneal tumors that may metastasize from the gonads and be a primary tumor.

PATIENT CONCERNS

An abdominal mass was detected in a 38-year-old woman during physical examination, which was accompanied by left renal obstructive hydrops. She was admitted to our institution for further investigation. The patient had no obvious clinical symptoms, and the levels of serum tumor markers did not signifificantly increase. Abdominal noncontrast enhanced and contrast-enhanced computed tomography revealed a retroperitoneal neoplasm that invaded the left ureter, thereby causing left hydronephrosis.

DIAGNOSES

Imaging examination characterized the tumor as malignant based on its invasion in the left ureter. Histopathology and immunohistochemistry confifirmed the resected tumor as a dysgerminoma. The primary gonad-derived germ cell tumor was not found in the pelvis; therefore, the patient was fifinally diagnosed with primary retroperitoneal germ cell tumor.

INTERVENTIONS

Preoperative examination was completed, and the retroperitoneal mass was resected.

OUTCOMES

During the short-term follow-up, no tumor recurrence was detected.

LESSONS

Primary retroperitoneal seminoma should be included in the differential diagnosis of primary retroperitoneal tumors in female patients. The primary retroperitoneal seminoma/anaplastic tumor has an obvious occupying effect and can easily invade the surrounding structures. However, surgical resection of such tumors is an optional treatment strategy.

Retroperitoneal cystic masses: magnetic resonance imaging features

The objective of this review is to discuss the clinical and histopathologic features, MRI characteristics, and management options of retroperitoneal cystic masses. Radiologists should be familiar with the MR imaging characteristics of retroperitoneal cystic masses to allow for a refined differential diagnosis, assist with lesion management, and prevent unnecessary invasive procedures.

Update on MR urography (MRU): technique and clinical applications

Magnetic resonance imaging of the upper tract (pyelocalyces and ureters) or MR Urography (MRU) is technically possible and when performed correctly offers similar visualization of the upper tracts and for detection of non-calculous diseases of the collecting system similar specificity but with lower sensitivity compared to CTU. MRU provides the ability to simultaneously image the kidneys and urinary bladder with improved soft tissue resolution, better tissue characterization and when combined with assessment of the upper tract, a comprehensive examination of the urinary system. MRU requires meticulous attention to technical details and is a longer more demanding examination compared to CTU. Advances in MR imaging techniques including: parallel imaging, free-breathing motion compensation techniques and compressed sensing can dramatically shorten examination times and improve image quality and patient tolerance for the exam. This review article discusses updates in the MRU technique, summarizes clinical indications and opportunities for MRU in clinical practice and reviews advantages and disadvantages of MRU compared to CTU.

A rare case of retroperitoneal and mesenteric lymphangiomatosis

Lymphagiomatosis are rare benign malformations of the lymphatic system. They are more commonly seen during childhood and are frequently asymptomatic and incidentally found in the adult patient. We report a case of a 31-year-old male who presented initially with melena. Computer tomography scan revealed multiple confluent, fluid-density lesions encasing the retroperitoneum and mesentery. A laparotomy and incisional biopsy of the mesenteric lesion was performed. Histologic examination demonstrated fibrofatty tissue with prominent, thick-walled endothelial-lined vessels. The histologic and computer tomography findings were consistent with a diagnosis of retroperitoneal and mesenteric lymphangiomatosis. The patient was subsequently discharged home well.

Aortoenteric fistula secondary to an Inflammatory Abdominal Aortic Aneurysm

Primary aortoenteric fistulas are rare, with the annual incidence of such fistulas estimated to be 0.007 per million. The most common predisposing conditions for primary aortoenteric fistulas are atherosclerotic abdominal aortic aneurysms or penetrating atherosclerotic ulcers. We illustrate a rare case of an inflammatory aortic aneurysm causing a primary aortic fistula, with a direct fistulous jet from the aorta to the bowel with resultant catastrophic bleeding. In contrast to atherosclerotic aneurysms, most inflammatory aneurysms are symptomatic and show dense perianeurysmal fibrosis and periaortic wall thickening. A direct jet of contrast extravasation from the aorta into a bowel loop, while rarely seen, remains the most specific sign of a primary aorta-enteric fistula. A comprehensive literature review of the clinical presentation, imaging features, and differential diagnosis of a primary aortoenteric fistula are also discussed.

Leiomyosarcoma of the Inferior Vena Cava with Hepatic and Pulmonary Metastases: Case Report

Sarcomas are connective tissue tumors accounting for only 1% of all adult malignancies. Leiomyosarcoma (LMS) is a sarcoma arising from smooth muscle cells, and accounts for 10-20% of all sarcomas. A subtype of LMS are those originating from the smooth muscle of blood vessels. Leiomyosarcoma of the inferior vena cava is a sarcomatous tumor, with less than 350 cases described in the literature. It carries a poor prognosis, with 5- and 10-year survival rates of 31.4% and 7.4%, respectively. We present a case of a 46-year-old female with no significant past medical history presented to the emergency department with mild abdominal pain and distention, early satiety, and weight loss for three weeks, found to have unresectable metastatic leiomyosarcoma of the inferior vena cava.

An interesting cause of chronic abdominal pain in a child

We encountered an eight-year-old boy who was subsequently diagnosed with a retroperitoneal ganglioneuroma. In view of the rarity of this tumour and its presentation, we are prompted to report this case.

Preoperative intravascular ultrasonographic evaluation of leiomyosarcoma of the inferior vena cava: A case report

Leiomyosarcoma of the inferior vena cava is a rare malignant tumor originating from smooth muscle cells of the vascular media. Its preoperative diagnosis by conventional noninvasive examinations such as abdominal ultrasonography, X-ray computed tomography, and magnetic resonance imaging, may be difficult because of their nonspecific findings. We present the case of a 72-year-old woman with leiomyosarcoma of the inferior vena cava diagnosed by intravascular ultrasonography.

Giant Melanotic Malignant Peripheral Nerve Sheath Tumor in the Pelvis: Contrast-Enhanced CT and 18F-FDG PET/CT Finding

Melanotic malignant peripheral nerve sheath tumor is an extremely rare tumor, which originates from the neural crest, and more than half the cases are associated with Carney complex (myxomas, spotty pigmentation, and endocrine abnormalities). Herein, we have presented a case of a melanotic malignant peripheral nerve sheath tumor, which is not associated with Carney complex. The patient underwent preoperative nonenhanced CT, contrast-enhanced CT, and F-FDG PET/CT scans, which showed a large pelvic tumor with heterogeneous enhancement and increased F-FDG uptake. Subsequently, the patient underwent complete resection of the tumor.

Poor prognosis of retroperitoneal mixed extragonadal germ cell tumors in an HIV-infected man with severe immunosuppression and bilateral cryptorchidism: a case report

Background

Nonseminomatous germ cell tumors (NSGCTs) represent one of the main groups of germ cell tumors (GCTs), and they have a more invasive course than seminomatous GCTs. Human immunodeficiency virus (HIV) positivity is considered to be a risk factor for testicular seminoma patients, but reports about HIV-infected individuals with NSGCTs are rare.

Case presentation

We report a case of a retroperitoneal mixed extragonadal germ cell tumor in an HIV-infected man who has been diagnosed with bilateral cryptorchidism since birth. A 30-year-old man presented with a large heterogeneously mixed echo mass located in the right lower abdomen according to an abdominal ultrasound; he was HIV-positive and had a low CD4 count of 70 cells/ml in the followed test, which suggested severe immunosuppression, and ultrasound-guided biopsy histology revealed a malignant yolk sac tumor of the testis. First, the patient received combination antiretroviral therapy; then, to relieve his symptoms, an exploratory laparotomy and retroperitoneal neoplasm resection under general anesthesia were performed for subsequent treatment. The postoperative histopathological examination indicated that the patient exhibited malignant mixed GCTs of the undescended testis that were composed predominantly of yolk sac tumors with foci of embryonal cell carcinoma and seminoma; It is a rare type in various GCTs, especially in HIV-infected patients. After the operation, the patient underwent computed tomography follow-up scans at 1 week and 2 weeks, and the results showed that the size of the right inguinal mass gradually increased, which suggested a poor outcome. To limit the growth of the tumors, right inguinal mass resection under local anesthesia was performed 17 days after the initial operation, and pathological examination revealed mixed GCT metastasis. Subsequently, the patient received salvage chemotherapy with a regimen of cisplatin, etoposide, and ifosfamide. Unfortunately, the patient died 1 week after the first cycle of chemotherapy because of severe immunosuppression, a low platelet count and cancer cachexia.

Conclusions

Because of severe immunosuppression, the treatment of advanced extragonadal NSGCTs in an HIV-infected patient resulted in a poor prognosis. This outcome should be considered in further research, and appropriate management for achieving long-term survival needs to be established.

A primary retroperitoneal anaplastic lymphoma kinase-positive anaplastic large cell lymphoma with tumor thrombosis

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) is a T cell subtype of non-Hodgkin’s lymphoma (NHL). Typically, lymphoma rarely infiltrates vascular structure. In this article, we present a case of retroperitoneal ALK-positive ALCL with splenic venous tumor thrombosis. A 62-year-old patient presented to our institute with the symptoms of epigastric pain, abdominal distension, and reduced bowel movement. Physical examination indicated no enlarged peripheral lymph nodes or abdominal mass. Laboratory workup revealed granulocytosis, abnormal coagulation function, and normal level of lactic dehydrogenase (LDH). Contrast-enhanced computed tomography (CT) showed a retroperitoneal mass with involvement of pancreas and duodenum and formation of splenic venous tumor thrombus. Ultrasonography-guided retroperitoneal lesion biopsy confirmed the diagnosis of ALK-positive ALCL. The patient was able to tolerate oral intake after two cycles of chemotherapy and showed no sign of lymphoma by positron emission tomography (PET)-CT after the fourth cycle of chemotherapy. In spite of its rarity, lymphoma should be taken into account as a differential diagnosis of other malignancies with tumor thrombosis.

Experience in the diagnosis and treatment of mesenteric lymphangioma in adults: A case report and review of literature

BACKGROUND

Mesenteric lymphangioma (ML) in adults is a very rare disease. We report six hospitalized adult patients with ML in our hospital between January 2013 and July 2018 to investigate the characteristics and prognosis of ML in adults.

CASE SUMMARY

The male-to-female ratio was 3:3, and the median age at diagnosis was 55.2 years. Clinical manifestations varied; however, most were acute cases (5/6). No history of trauma was reported. None (0/6) of the patients were accurately diagnosed with ML in the emergency and outpatient departments. Mesenteric cysts were identified in four patients (66.7%) by abdominal ultrasound and in five patients (83.3%) by computed tomography. ML was postoperatively confirmed by pathology. Most MLs (4/6) were associated with infection of other systems. ML was located in the mesentery of the small intestine (n = 4), ileum (n = 1) and rectum (n = 1). Cyst fluid was clear (n = 4), chylous (n = 1) and bloody (n = 1). Surgical procedures included complete tumor removal and partial intestinal excision (n = 6). Recurrence and adhesive intestinal obstruction were not observed during the 3-12 mo follow-up period.

CONCLUSION

ML in adults is a rare benign acquired disease that can be cured by surgical treatment. Infection may be a cause of ML.

Desmoid-type fibromatosis mimicking cystic retroperitoneal mass: case report and literature review

Background

Retroperitoneal desmoid-type fibromatosis (DF) is an uncommon mesenchymal neoplasm presenting as a firm mass with locally aggressive features. It usually manifests as a well-circumscribed or ill-defined, solid mass on cross-sectional imaging. Cystic changes of DF have been described in the literature in association with prolonged medical treatment or abscess formation. However, spontaneous cystic change is rarely reported.

Case presentation

Here we report the case of a 46-year-old patient with a DF mimicked a large cystic tumor in the retroperitoneum. Ultrasonography and computed tomography were performed in order to search for localizations and characteristics of the cystic tumor. Radiological findings showed an oval cystic mass with a relatively thick wall, measuring 18.3 × 12.3 × 21.5 cm in the left upper abdomen. Laparoscopic spleen-preserving distal pancreatectomy was performed and histopathological examination by immunohistochemical study enabled us to diagnose a DF invading the pancreatic parenchyma. The patient remained asymptomatic during an 8-month follow up period.

Conclusions

We report an extremely rare case of retroperitoneal DF with spontaneous cystic change. DF can manifest as a mainly cystic mass with a thick wall, as in our case, which makes the correct diagnosis difficult. DF should be included in the preoperative differential diagnosis of a cystic retroperitoneal mass, regardless of its rarity.

Giant fibroepithelial polyp of the thigh and retroperitoneal fibromatosis in a young woman: a rare case

We present a case of 20-year-old woman who presented with a large pedunculated skin covered mass lesion arising from the left thigh, measuring 40 × 25 cm, with no history of pain or skin ulceration and a feeling of a lump with dragging pain in the left side of the abdomen for about 7 years. Subsequently, ultrasound, contrast-enhanced computed tomography, and magnetic resonance imaging of abdomen and left thigh region were carried out. The lesion was broad-based toward the left upper thigh with a central core of interspersed fat supplied by branches of the superficial and deep femoral arteries. Another lesion was seen in the left retroperitoneum anterior to the psoas muscle in a left paravertebral location encasing the left common iliac vessels extending into the left pelvic cavity and inguinal region inferiorly. The lesion showed dense post-acoustic shadowing on ultrasound, mild enhancement on contrast-enhanced computed tomography, and appeared hypointense on T1- and T2-weighted images. A left thigh lesion was excised, whereas incisional biopsy was done for the left retroperitoneal lesion. The diagnosis of a giant fibroepithelial polyp arising from the left thigh and left retroperitoneal fibromatosis was made. This is the first report of such a giant fibroepithelial polyp arising from the thigh with associated retroperitoneal fibromatosis.

Retroperitoneal Leiomyosarcoma From the Radiologic Pathology Archives

Leiomyosarcoma is a malignant neoplasm that shows smooth muscle differentiation. It is the second most common sarcoma to affect the retroperitoneum. Retroperitoneal leiomyosarcomas may grow to large sizes before detection and may be an incidental finding at imaging. When symptomatic, retroperitoneal leiomyosarcoma may cause compressive symptoms, including pain. Retroperitoneal leiomyosarcoma most commonly manifests as a large soft-tissue mass, with areas of necrosis. The most frequent pattern of growth is an entirely extravascular mass. Less commonly, leiomyosarcoma may demonstrate both extravascular and intravascular components. Rarely, retroperitoneal leiomyosarcomas are completely intravascular, typically arising from the inferior vena cava. Given its variable imaging features, a large variety of neoplastic and nonneoplastic conditions are included in the differential diagnosis of retroperitoneal leiomyosarcoma. In this review, the authors discuss retroperitoneal leiomyosarcoma, with emphasis on the pathologic basis of disease, and illustrate the multimodality imaging appearances of retroperitoneal leiomyosarcoma using cases from the Radiologic Pathology Archives of the American Institute for Radiologic Pathology. The authors review important differential considerations of retroperitoneal leiomyosarcoma, focusing on the extravascular pattern of growth, and emphasize clinical and imaging features that help radiologists differentiate leiomyosarcoma from the most frequent mimics. The information presented in this review will aid radiologists in fulfilling their key roles in the diagnosis, operative planning, and follow-up of patients with retroperitoneal leiomyosarcoma.

Practical Approach to Adrenal Imaging

Various pathologies can affect the adrenal gland. Noninvasive cross-sectional imaging is used for evaluating adrenal masses. Accurate diagnosis of adrenal lesions is critical, especially in cancer patients; the presence of adrenal metastasis changes prognosis and treatment. Characterization of adrenal lesions predominantly relies on morphologic and physiologic features to enable correct diagnosis and management. Key diagnostic features to differentiate benign and malignant adrenal lesions include presence/absence of intracytoplasmic lipid, fat cells, hemorrhage, calcification, or necrosis and locoregional and distant disease; enhancement pattern and washout values; and lesion size and stability. This article reviews a spectrum of adrenal pathologies.

Giant adrenal pseudocyst: A rare diagnosis

We present a rare case of giant adrenal pseudocyst as a cause of right upper quadrant (RUQ) pain and highlight the typical multimodality imaging features. The case demonstrates the imaging features associated with giant adrenal pseudocysts to aid accurate and timely diagnosis. Despite the rarity of these lesions they are important to consider as benign lesions can closely mimic malignant ones. Unenhanced and contrast-enhanced CT is the imaging of choice for adrenal cysts. However, MRI can provide more exquisite assessment of cystic, solid and enhancing components. Pseudocysts can be purely cystic, mixed or solid. Classically, adrenal pseudocysts are described as cystic lesions (of homogenous water density) with a fibrous wall and thin internal septations. Mural/septal calcification is commonly demonstrated due to haemorrhage, this is discernible from central/amorphous calcification seen in malignant disease. As in this case, pseudocysts can contain solid components or layering secondary to haemorrhage. The key to differentiating organised haematoma from tumour is the lack of enhancement. If serial imaging is undertaken in these patients rapid changes in the solid components may be seen reflecting resolving haematoma. Adrenal pseudocysts are rare and have a wide differential. Cystic adrenal lesions warrant multimodality assessment as their imaging features aid diagnosis and differentiation from malignant disease. We suggest that MRI plays a complimentary role to CT. CT is superior at demonstrating mural/septal calcification but MRI aids in determining cystic components and differentiating haemorrhage from tumour.

A giant adrenal cyst with an uncertain preoperative diagnosis causing a dilemma in management

Giant Adrenal cysts are rare differentials of retroperitoneal cysts that often present dilemma in diagnosis. A man presented with a huge retroperitoneal cyst and an uncertain preoperative diagnosis. Initial working diagnosis of urinoma and an attempt at drainage had to be abandoned for complete excision before obtaining a histological diagnosis.