Imaging of uncommon retroperitoneal masses

Cross-sectional Imaging Features of Primary Retroperitoneal Tumors and Their Subsequent Treatment

Basically malignant tumors in the retroperitoneal region arise from a heterogeneous group of tissues: mesodermal, neurogenic, germ cell, and lymphoid. Although rare, benign tumors and cystic masses can be also encountered in retroperitoneal space. Developments in computed tomography (CT) and magnetic resonance imaging (MRI) have contributed to both diagnosis and staging of the retroperitoneal tumors. High spatial resolution and superiority in calcification make CT indispensable; on the other hand, MRI has a better soft-tissue contrast resolution which is essential for the assessment of vascular invasion and tissue characterization. The aim of this article is to review the CT and MRI features of retroperitoneal tumors and their subsequent management.

Retroperitoneal nodular fasciitis: a benign etiology on the differential diagnosis of malignant gastric outlet obstruction

Nodular fasciitis is a relatively rare, benign and proliferative lesion that is not typically found in the retroperitoneal (RP) space and has not been previously reported as a cause of gastric outlet obstruction (GOO). GOOs are frequently associated with malignancies, however, benign etiologies should be considered as well. We report the first case of GOO secondary to nodular fasciitis in the form of a spontaneously regressing RP mass that was initially concerning for malignancy.

Large retroperitoneal isolated fibrous cyst in absence of preceding trauma or acute pancreatitis

BACKGROUND

Isolated retroperitoneal cystic masses are uncommon with an estimated incidence of 1/5750 to 1/250,000. The majority present with size related symptoms, complications, or a mass. Approximately a third of patients are asymptomatic and are diagnosed incidentally. Aetiologies of retroperitoneal cystic masses (RPC) include mesenteric, omental, splenic and enteric duplication cysts. Neoplastic RPCs can be divided into epithelial (mucinous or serous cystadenoma), mesothelial (mesothelioma), germ cell (cystic teratoma) and cystic changes in a solid neoplasm (paraganglioma, neurilemmoma, sarcoma).

CASE PRESENTATION

A 53 year-old man presented to us with abdominal pain related to a large mass in his left upper quadrant with associated anorexia and weight loss. He gave no history of previous trauma and denied having symptoms or a history of pancreatitis. He said he had felt this mass increasing in size over the course of several years. Clinical examination of his abdomen revealed a large firm left sided mass extending to his left upper quadrant. Imaging with computed tomography (CT) and magnetic resonance imaging cholangio-pancreatogram (MRCP) revealed a 13.7 cm × 12.2 cm × 10.9 cm cystic lesion in the retroperitoneum which was separate from the kidney, pancreas, spleen and bowel. At laparotomy, this mass was easily dissected from the surrounding viscera and was excised completely intact. Histopathological assessment found the mass to be a large fibrous pseudocyst with no epithelial lining.

CONCLUSION

We present a rare case of an isolated large retroperitoneal fibrous pseudocyst unrelated to previous pancreatitis which was successfully managed with surgery.

Retroperitoneal tumors in the pelvis: a diagnostic challenge in gynecology

Retroperitoneal tumors can pose a diagnostic and therapeutic challenge to gynecologists because of their rarity, late presentation, and complex anatomical location in the retroperitoneum. This article reviews the diagnosis and management of retroperitoneal tumors in the pelvis, and highlights the potential pitfalls that may be faced by gynecologists.

'Primary extrarenal Wilms' tumour': rare presentation of a common paediatric tumour

Wilms' tumour (nephroblastoma), the most common abdominal malignancy of childhood, occurs primarily as a malignant renal tumour. Extrarenal Wilms' tumour is rare with occasional reports from the Indian subcontinent. The various locations of extrarenal Wilms' tumour include retroperitoneum, uterus, skin and thorax. In this report we will discuss the imaging features highlighting the imaging differential diagnosis in a case of retroperitoneal (extrarenal) primary Wilms' tumour.

An unusual fat-containing presacral tumor in an elderly patient

The authors present a case of a presacral myelolipoma diagnosed in an 84-year-old male patient with longstanding pelvic pain and past medical history of bladder cancer. Pelvic computed tomography (CT) revealed a well-encapsulated and lobulated presacral mass, with mixed fat and soft-tissue attenuation. Magnetic resonance (MR) imaging provided further confirmation of macroscopic intralesional fat and excluded either adjacent bone invasion or bladder cancer recurrence. A presacral myelolipoma was suspected based on imaging findings, with liposarcoma and teratoma having also been considered for the differential diagnosis. The histological confirmation of the tumor was only attained postoperatively. This case report alerts to the possible presacral location of myelolipomas, which should be considered for every fat-containing lesion detected in this region. The main clinical, imaging, and differential diagnoses of this entity are reviewed in this paper.

Incidental discovery of testicular microlithiasis: what is the importance of ultrasound surveillance? Two case reports

Many studies have demonstrated an association between diffuse bilateral testicular microlithiasis (TM) and gonadal and extragonadal germ cell tumors. Nevertheless, it is still uncertain whether ultrasound surveillance is really necessary in patients with TM in the absence of other risk factors such as previous testicular cancer, a history of cryptorchidism or testicular atrophy. We report the cases of a 33- and a 39-year-old man presenting with a retroperitoneal extragonadal tumor. The first patient underwent an MRI examination in order to rule out a lumbosacral hernia: MRI images showed no slipped disks but a voluminous retroperitoneal solid mass. The histological analysis revealed an immature teratoma. The second patient came to the emergency department complaining of abdominal pain, vomiting, weight loss and mild jaundice: ultrasound examination showed a large, ill-defined heterogeneous abdominal mass, confirmed by CT and MRI examination. The histology diagnosed a yolk sac tumor. In both patients, the testicular sonography was performed to rule out a focal lesion, but it displayed bilateral TM without a focal testicular mass. Based on our direct experience, we highlight the importance of annual ultrasonographic surveillance of the testis and the retroperitoneal space in patients with occasionally detected TM.

Giant cystic leiomyoma of the uterus occupying the retroperitoneal space

A 31-year-old nulliparous woman visited our hospital complaining of abdominal distension. Abdominal ultrasonography and computed tomography revealed a 40 × 40 × 30-cm, multilocular cystic mass extending from the upper abdomen to the pelvis. Magnetic resonance imaging (MRI) revealed a cystic tumor that was hypointense on T1-weighted images and was heterogeneously hyperintense on T2-weighted images. The final diagnosis was an 8 kg leiomyoma with cystic degeneration. Uterine leiomyomas are common benign tumors in females of reproductive age. However, subserosal leiomyomas with complete cystic degeneration of the retroperitoneal space are rare, and they are difficult to accurately diagnosis without pathological examination.

Solid malignant retroperitoneal masses-a pictorial review

Primary retroperitoneal masses are a rare but important group of neoplasms. Cross-sectional imaging has revolutionised the investigation of patients with retroperitoneal neoplasms. Both computed tomography (CT) and magnetic resonance imaging (MRI) can contribute to tumour diagnosis, though histological confirmation is often required because of the considerable overlap of imaging features. Cross-sectional imaging is key to the pre-operative staging and planning of retroperitoneal masses, though ultrasound may also help in certain instances. Imaging also helps to select and guide the site to biopsy from these usually large and heterogeneous neoplasms. This article aims to review many of the primary retroperitoneal neoplasms that may be encountered by the radiologist.

Early gastric cancer with neurofibroma mimicking a metastatic node: a case report

Neurofibromas are benign tumors that originate from the peripheral nerves, including neurites and fibroblasts. Generally, a solitary neurofibroma is located in the skin and rarely in other places. A 72-year-old female suffered from epigastric discomfort for 2 months. Endoscopic findings showed an early gastric cancer type IIc at the antrum. Abdominal computed tomography revealed early gastric cancer with a 1.6 cm-sized metastatic node posterior to the duodenum. Laparoscopic assisted distal gastrectomy and retro-pancreatic dissection were performed uneventfully. Histological examination revealed gastric adenocarcinoma, invading the mucosa without nodal metastasis, and a neurofibroma. Herein, we present a case of a gastric cancer patient with a solitary retroperitoneal neurofibroma which mimicked a distant metastatic node.

A comprehensive review of the retroperitoneal anatomy, neoplasms, and pattern of disease spread

A clear understanding of the normal anatomy and pattern of disease spread is important in evaluating many retroperitoneal disorders. Primary retroperitoneal tumors are uncommon, accounting for 0.1%-0.2% of all malignancies in the body; 80%-90% of all primary retroperitoneal tumors are malignant. The primary retroperitoneal neoplasms can be divided into solid or cystic masses. The solid neoplasms can be classified according to their tissue of origin into 3 main categories: mesodermal tumors, neurogenic tumors, and extragonadal germ cell tumors. Computed tomography and magnetic resonance imaging play a vital role in the localization, characterization, evaluation of the extent of local invasion, assessment of metastases, and determination of treatment response for these tumors. The diagnosis of a primary retroperitoneal malignancy is often challenging owing to overlap of imaging findings. A definitive diagnosis can be established only at histopathologic analysis. However, knowledge of the important tumor characteristics, growth pattern, and vascularity can assist in narrowing the differential diagnosis.

[Lymphoma and arteries: peri- or intravascular?]

PURPOSE

Lymphoma is a polymorphous disease that does not spare arteries. Arterial involvement may be perivascular or intravascular, with different prognostic and therapeutic implications.

PATIENTS AND METHODS

We present here one case of perivascular lymphoma and another case of intravascular lymphoma in order to highlight the specific features of each type.

RESULTS

The first patient was a woman who presented a pseudo-aneurysmal anterior iliac artery due to a non-Hodgkin lymphoma with subsequent bilateral pyelocalyceal distension. The second patient was a man who developed intravascular lymphomatosis expressed by an aneurysm of the common femoral then the primitive iliac artery.

CONCLUSION

The distinction between perivascular and intravascular arterial involvement is based on a range of features and is essential for an optimal care of patients with lymphoma.

Non-Invasive Diagnosis of Abdomino-Pelvic Masses: Role of Multimodality Imaging

Recent advances in radiology have greatly increased the ability to make highly accurate diagnosis. Biopsy of many commonly seen lesions is no longer performed as the radiological findings are pathognomonic. This gives rise to the concept of ‘virtual biopsy’, a term coined on the lines of other imaging techniques such as virtual colonoscopy. Virtual biopsy is not a new imaging technique but a new concept which refers to the use of existing imaging modalities to evaluate the morphological features of tumors and arriving at a non-invasive diagnosis with a high degree of confidence obviating the need for true biopsy. Elements of virtual biopsy have already been incorporated into some evidence-based guidelines, and it is expected that with further technological advancements, an increasing number of tumors may be diagnosed and managed accordingly. A wider acceptance of virtual biopsy could further reduce the need for invasive biopsies and its attendant costs and risks. In this review article, we use index cases to further emphasize this concept.

Retroperitoneal lipomas: A case report

Lipomas are mesenchymal tumors characterized by the abnormal proliferation of adipocytes. We describe a case of retroperitoneal lipomas in a patient with chronic lymphatic leukemia, who was referred to our sonography unit for a regular (6-month) follow-up scan. She had no abdominal symptoms of note. The sonographic examination revealed two well-defined, hyperechoic, oval-shaped masses: the first situated between the posterior wall of the stomach, the duodenum, and the head of the pancreas; the second lying craniomedial to the left kidney. Neither of the masses exhibited intralesional vascularization on color Doppler imaging. Retrospective examination of previous CT scans revealed that the lesions had been present for the past 4 years. Their slow growth was consistent with the suspicion of retroperitoneal lipomas, and this diagnosis was confirmed by magnetic resonance imaging. CT and MRI are the imaging studies of choice for diagnosing retroperitoneal lipomas, but ultrasonography is ideal for the follow-up of these patients because it is repeatable and relatively low in cost.

Imaging of the retroperitoneum

The retroperitoneum is the compartmentalized space bounded anteriorly by the posterior parietal peritoneum and posteriorly by the transversalis fascia. It extends from the diaphragm superiorly to the pelvic brim inferiorly. This article discusses clinically relevant anatomy of the abdominal retroperitoneal spaces, their cross-sectional imaging evaluation with computed tomography and magnetic resonance imaging, and the imaging features of common retroperitoneal pathologic processes.