A total colectomy with J-pouch of the ileum was performed. Lymphome et artères : une atteinte périvasculaire ou intravasculaire ? 6, 12 September 2017 | RadioGraphics, Vol. 36, No. Figure 4 Leiomyosarcoma with IVC involvement in a 53-year-old man. While benign bland thrombus does not show any contrast enhancement, leiomyosaroma of the IVC enhances on both early and delayed (10-minute) contrast-enhanced images and causes more expansion of the IVC (13,14). Retroperitoneal fibrosis does not displace the aorta and IVC anteriorly, as lymphoma or metastatic nodes often do, but causes tethering of these structures to the underlying vertebrae. Pathologically, schwannoma is encapsulated and extends along the course of a nerve, with the nerve of origin flattened against the periphery of the tumor. On the left a patient with a lung carcinoma. 4, International Journal of Surgery Case Reports, Vol. Soft tissue masses with “cyst-like” appearance on MR imaging: distinction of benign and malignant lesions. In peritoneal carcinomatosis we see tumor nodules along the peritoneal lining (arrow), omental tumor deposits, and bowel obstruction. In some cases, further imaging with CT or MR may be required, being the latter preffered owing to lack of radiation exposure Images for this section: Fig. The differential diagnosis of a solid mass with calcification includes teratoma, malignant fibrous histiocytoma, chondrosaroma, Ewing sarcoma, dedifferentiated liposarcoma, and synovial sarcoma. 37, No. The histopathologic findings from biopsy showed ganglioneuroma. A typical feature of pseudomyxoma peritonei is scalloped indentation of the surface of the liver and spleen. CT shows a large thin-walled unilocular or multilocular cystic mass (Fig 28) with attenuation values ranging from that of fat (caused by chyle) to that of fluid. Contrast enhancement is heterogeneous, with nonenhancing cystic components and enhancing solid components. This tumor is histologically identical to malignant ovarian surface epithelial tumors. The retroperitoneum is involved in 7% of cases. Perivascular Epithelioid Cell Tumor.—Perivascular epithelioid cell tumor (also called PEComa) is a mesenchymal tumor that is composed of distinctively perivascular epithelioid cells, which are radially arranged cells around a vascular lumen. In Peritoneum and Mesentery - part I: Anatomy the normal anatomy and physiology of the peritoneum and peritoneal cavity are discussed. There are also some enhancing septa. Radiography shows characteristic bilateral symmetric osteosclerosis of the metaphyseal-diaphyseal region of the long bones, with sparing of the epiphysis and lesser involvement of the flat bones and axial skeleton. Histopathologically, pancreatic pseudocyst is an encapsulated collection of pancreatic fluid, with an epithelial lining, and the fluid contains amylase. Lymphangioma has enhancing septa. Axial CT image of the upper part of the abdomen shows an iso- to hypoattenuating mass in the left paravertebral region, with fine specks of calcification (arrowhead). Axial CT image shows a large heterogeneous mass (arrows) in the retroperitoneum. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. 88, No. The findings from histopathologic examination disclosed that this mass was a perivascular epithelioid cell tumor, subtype angiomyolipoma. Notice that this lesion is not of low attenuation. At CT, small schwannomas are round, well defined, and homogeneous, but large schwannomas may be heterogeneous in appearance. Lymphangioma can be seen in perirenal, pararenal, or pelvic extraperitoneal spaces and can involve more than one compartment. A well-defined cystic lesion is seen in the retroperitoneum, more commonly in the perirenal space. It is a very aggressive tumor with a poor prognosis. A multilocular cyst with thick septa and calcifications that is located in the right lower quadrant is likely to be a pseudomyxoma retroperitonei, most likely caused by a ruptured mucocele of the appendix. omental cake and ascites. On the left again a more typical case with a low density tumor located in the greater omentum (upper image) and the gastrosplenic ligament (lower image). Whole-body short inversion time inversion-recovery (STIR) MR imaging is a sensitive method for the detection of bone lesions associated with this condition (56).Figure 29 Lymphangiomatosis in a 26-year-old man. Uptake will be seen in active inflammation and absent in metabolically inactive disease 3. Enhancement of the wall and solid components may be found (Fig 32). Radiology of the Retroperitoneum: Case-Based Review. In the retroperitoneum, schwannoma is commonly located in the paravertebral region and, less commonly, adjacent to the kidney, presacral space, and abdominal wall. CT and MR imaging are valuable in the evaluation of retroperitoneal masses, particularly in staging and the assessment of vascular invasion. Other solitary solid tumors like ... can have the same presentation. The lower portions of the ureters may be pinched medially, with resultant hydroureteronephrosis. Viewer. Histopathologically, myelolipoma is well encapsulated, and it has myeloid and erythroid precursors, with mature adipose tissue and occasionally hemorrhage and calcification (22). Plasmacytoma progresses to myeloma in 50% of cases (43,44).Figure 22 Extramedullary plasmacytoma in a 68-year-old man. Vascular Study-Vascular studies are … Extramedullary hematopoiesis is seen in hemoglobinopathies, myelofibrosis, leukemia, lymphoma, and carcinomas. Although extramedullary plasmacytoma is most common in the aerodigestive tract (80%), it can be found in almost any organ. Axial noncontrast CT image shows a large homogeneous mass (arrow) in the retroperitoneum. Before a diagnosis of primary extragonadal germ cell tumor is made, a primary gonadal lesion should be excluded because retroperitoneal metastasis is seen in 30% of gonadal tumors. Fat-containing lesions of the retroperitoneum: radiologic-pathologic correlation, Leiomyosarcoma of the retroperitoneum and inferior vena cava: radiologic-pathologic correlation, Imaging primary and secondary tumor thrombus of the inferior vena cava: multi-detector computed tomography and magnetic resonance imaging, Imaging and clinical spectrum of rhabdomyosarcoma in children, Imaging of primary chondrosarcoma: radiologic-pathologic correlation, Primary retroperitoneal extraskeletal mesenchymal chondrosarcoma: a computed tomography diagnosis. Axial CT image shows a homogeneous well-defined lobulated cystic mass (arrow) in the retroperitoneum. When an adjacent organ has rounded edges, which indicates that the retroperitoneal mass does not arise from that organ, this finding is called a “negative beak sign.” Option C is not the best response. Viewer. Occasionally, high-flow blood vessels may be seen. Paragangliomas are more aggressive tumors, with 22%–50% having metastases, compared with 2%–10% of adrenal pheochromocytomas. Notice the sheet-like thickening of the peritoneum. At CT, myelolipoma is depicted as a heterogeneous mass with areas of fat and enhancing soft tissue (Fig 9). 1, 2 = cursors used to measure attenuation values. The occurrence of septa, compression of intestinal loops, and a lack of fluid in dependent recesses and mesenteric leaves differentiate lymphangioma from ascites. There is a multi-cystic mass extending from the pelvis along the right paracolic gutter to the upper abdomen. Histologically, liposarcoma is classified, in increasing order of malignancy, into four subtypes: well-differentiated, myxoid, pleomorphic, and round cell subtypes. Can the MRI signal of aggressive fibromatosis be used to predict its behavior? The imaging features of a peritoneal inclusion cyst are non-specific except that it has to be located in the pelvis: On the left a transvaginal ultrasound demonstrating a multicystic pelvic lesion next to the uterus, which proved to be a peritoneal inclusion cyst. Viewer It is useful to observe the displacement of normal anatomic structures (, 1).Anterior displacement of retroperitoneal organs (eg, kidneys, adrenal glands, ureters, ascending and descending colon, pancreas, portions of the duodenum) strongly suggests that … The recurrence rates are high, and metastases to liver, lung, bones, and brain may be seen (1,2). Axial T1-weighted spin-echo MR image shows a well-defined homogeneous mass with low signal intensity (straight arrow) and an absence of clear demarcation from the IVC (curved arrow). 3, No. 2 In TB the peritoneum is usually very thick (arrow). Typically, there is immediate peripheral enhancement after contrast material administration and homogeneous delayed (10-minute) enhancement in the center, likely caused by slow lymphatic flow into the cystic mass (58). Axial CT image shows a large heterogeneous mass with areas of curvilinear calcification (arrow) in the retroperitoneum.Figure 19Download as PowerPointOpen in Image Positron emission tomography (PET) shows a high uptake of fluorine 18 fluorodeoxyglucose (FDG) in viable tumor, but there is no uptake in fibrosis. Histopathologically, retroperitoneal fibrosis is characterized by ill-defined plaquelike fibrous proliferation around the aorta, iliac arteries, IVC, and ureters. Axial CT image shows edema (curved arrow) in the peripancreatic region and a unilocular cystic collection (straight arrow) in the left anterior pararenal space, a finding that is consistent with a pancreatic pseudocyst. 3, Clinical Nuclear Medicine, Vol. Epidermoid cyst is more common in women. From the Imaging Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195 (P.R. Mesenteric thickening can be seen that is caused by dilated or obstructed lymphatic vessels. This feature is highly suggestive of leiomyosarcoma.Figure 4Download as PowerPointOpen in Image Retroperitoneal spaces based on the traditional concept of retroperitoneal anatomy. Notice that CT does not always appreciate the septations, although the specimen clearly shows multiple septations. The typical CT appearance is hyper- or isoattenuating round or lobulated masses in the paravertebral region, with or without macroscopic fat (Fig 27). Leiomyosarcoma.—Leiomyosarcoma is the second most common (28%) primary retroperitoneal sarcoma (1). Sclerosing mesenteritis (2) There is hardly any scalloping of the liver. 5, International Journal of Gynecological Cancer, Vol. Liposarcoma.—Liposarcoma is the most common (33%) primary retroperitoneal sarcoma (1). 97, No. Mixed signal intensity and a fluid-debris level can be seen in hemorrhagic lesions. Usually there is accompanying abnormality of the terminal ileum and lymphadenopathy. Hypervascular masses were, with rare exceptions, malignant. jun06 1, 29 November 2013 | Insights into Imaging, Vol. Tailgut cyst originates from embryonic hindgut remnants. Compared with mature teratoma, immature teratoma is less common (<1%), contains more than 10% undifferentiated tissue, and is seen in a younger age group (<20 years). On the left a patient with a typical carcinoid with central calcification (blue arrow). Axial STIR MR image obtained at the level of the aortic bifurcation shows a well-defined hyperintense mass (arrow) lateral to the lower part of the abdominal aorta, a finding that is consistent with a paraganglioma in the organ of Zuckerkandl. Viewer Mesenteric fibromatosis - Desmoid (2) Al-though there is substantial overlap of computed tomographic (CT) findings in various retroperitoneal cysts, some CT features, along with clinical characteristics, may suggest a specific diagnosis. On the left another image of the same patient. In the retroperitoneum, the most common site for a paraganglioma is the organs of Zuckerkandl, which are located anterior to the aorta at the level of the origin of the inferior mesenteric artery. 6, Journal of the Korean Society of Radiology, Vol. Compared with the mesenchymal tumors, neurogenic tumors occur in a younger age group and are more likely to be benign and have a better prognosis. A mass with fat and calcification or teeth is pathognomonic of teratoma. The imaging appearances are similar to those of gonadal germ cell tumors. 41, No. Peritoneal inclusion cyst (4) The posterior pararenal space (PPRS) is located between the posterior renal fascia (PRF) and the transversalis fascia (TF). The most common location of immature teratoma is near the upper pole of the left kidney (37). Lytic lesions (arrows) are depicted in the vertebra.Figure 29Download as PowerPointOpen in Image 9, No. Epidermoid cyst is a congenital ectodermal cyst that is caused by desquamation of epithelial cells. There is associated bowel wall thickening due to a desmoplastic reaction. These tumors are large at the time of clinical presentation and often involve adjacent structures. Figure 7 Angiosarcoma in a 61-year-old woman. Desmoid tumor (deep fibromatosis, aggressive fibromatosis, well-differentiated fibrosarcoma) is one of the forms of deep fibromatosis that constitutes 1.5%–3% of all soft-tissue masses (24) and accounts for less than 1% of retroperitoneal tumors. Note also the mass (arrowhead) in the posterior pararenal space, posterior to the right kidney.Figure 13Download as PowerPointOpen in Image Computed tomography (CT) and magnetic resonance (MR) imaging play an important role in characterization and in the assessment of the extent of the disease and involvement of adjacent and distant structures. Nonpancreatic pseudocyst is usually asymptomatic, without elevation of serum amylase or lipase levels. The small bowel mesentery is the most common site. Although the differential diagnosis of retroperitoneal masses can be narrowed down to a certain extent on the basis of imaging characteristics, patterns of involvement, and demographics, there is still a considerable overlap of imaging findings for these masses, and histologic examination is often required for definitive diagnosis. 3, No. Calcification is seen in as many as 30% of cases and is an important sign of dedifferentiation. 1, 21 April 2016 | Medical & Biological Engineering & Computing, Vol. Tailgut cyst is most commonly seen in the presacral space, between the rectum and sacrum. 216, No. It is the result of chronic inflammation with an unclear pathogenesis. Erdheim-Chester disease is associated with perinephric fibrosis and bone lesions. 19, No. The mass is displacing the IVC. This proved to be a metastasis of the lung carcinoma. CT and MR imaging are valuable in the evaluation of retroperitoneal masses, particularly in staging and the assessment of vascular invasion. 1, 4 July 2018 | Journal of Medical Imaging and Radiation Oncology, Vol. Axial CT image shows a large multicystic mass with specks of calcification (arrowheads) in the retroperitoneum. Then solid retroperitoneal masses are covered, grouped into solid neoplastic masses and solid nonneoplastic masses. Retroperitoneal fibrosis can be secondary to drugs, malignancy, hemorrhage, inflammatory conditions, infection, radiation, chemotherapy, renal trauma, and amyloidosis. Lipomatosis is seen commonly in the pelvis and along the perirectal and perivesicular spaces and is seen less commonly in the abdominal retroperitoneum. CT shows a complex cystic mass, with areas of fat and calcification. Retroperitoneal Masses: Magnetic Resonance Imaging Findings with Pathologic Correlation Current Problems in Diagnostic Radiology, Vol. Also called Multilocular peritoneal inclusion cyst or Benign cystic mesothelioma. Lymphangioma can manifest in the first 2 years of life with abdominal distention or pain. Secondly we have to realize that any loculated fluid collection due to infection, i.e. Moderate to marked contrast enhancement is demonstrated on contrast-enhanced images. Generally, ganglioneuroma is larger and has more calcification than a nerve sheath tumor. Viewer. The hormonally active ovaries secrete fluid that becomes loculated in the pelvis. In patients with lymphangioleiomyomatosis, a retroperitoneal cystic mass is assumed to be a lymphangioleiomyoma unless there are clinical indications of abscess or tumor (59).Figure 30 Lymphangioleiomyoma in a 33-year-old woman. Lymphangioma is a benign lesion of vascular origin. It is one of the most common primary retroperitoneal neoplasms. 2, © 2021 Radiological Society of North America, CT characteristics of primary retroperitoneal neoplasms, Primary retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic diagnostic clues, MR imaging of soft-tissue masses of the extraperitoneal spaces, Gerota versus Zuckerkandl: the renal fascia revisited, CT of the extraperitoneal space: normal anatomy and fluid collections, CT and MR imaging of extrahepatic fatty masses of the abdomen and pelvis: techniques, diagnosis, differential diagnosis, and pitfalls, Retroperitoneal liposarcoma: MR characteristics and pathological correlative analysis. Viewer. Urinoma is a collection of extravasated urine that is found secondary to trauma or iatrogenic causes. Viewer. The histopathologic findings from biopsy showed that this mass was a primary retroperitoneal embryonal carcinoma.Figure 17Download as PowerPointOpen in Image The mass compresses the vascular structures and displaces the bowel loops. Other sarcomas can also appear cystic after chemotherapy because of tumor necrosis and hemorrhage (51). Viewer. Ganglioneuroblastoma and Neuroblastoma.—Ganglioneuroblastoma is an intermediate-grade tumor that has elements of benign ganglioneuroma and malignant neuroblastoma. These masses include neoplasms such as lymphoma, round cell tumors, and desmoid tumors, as well as nonneoplastic masses such as retroperitoneal fibrosis and Erdheim-Chester disease. Paraaortic lymph nodes are involved in 25% of the patients with Hodgkin lymphoma and 55% of the patients with non-Hodgkin lymphoma. Lymphangioma is often closely associated with the small bowel. A cyst located in the subdiaphragmatic space is likely to be a bronchogenic cyst. You can have a large mesenteric component and such a small attachment to the bowel, that you may not appreciate it. Figure 24 Active retroperitoneal fibrosis in a 49-year-old man. 1, Seminars in Ultrasound, CT and MRI, Vol. If the address matches an existing account you will receive an email with instructions to reset your password. So there are two distinct patterns. Axial contrast-enhanced CT image obtained at the level of the L5 vertebra shows a large mass with areas of necrosis in the right posterior pararenal and paravertebral spaces. Although paraganglioma may be “bright” (Fig 16), the tumor is usually complex and heterogeneous (because of hemorrhage) (28) and almost never demonstrates “lightbulb” high signal intensity with current imaging techniques (35). The nerve of origin is often difficult to identify. Fibrosis has low signal intensity on T2-weighted MR images, with minimal enhancement. Usually it is a lymphangioma. Serpentine flow voids may be seen on T2-weighted MR images. European radiology. 207, No. Calcification is rarely seen. The lymph nodes most often are of low attenuation (caseated). It tells us that the lesion is well vascularized. Primary retroperitoneal neoplasms are uncommon in children. Hemorrhage is more common in larger tumors. Figure 9 Myelolipoma in a 44-year-old woman. Calcification can be punctate, mottled, or curvilinear (Fig 11). 1, 14 December 2018 | RadioGraphics, Vol. Intra-abdominal and Retroperitoneal Masses Fig. At MR imaging, lymphoma is usually isointense on T1-weighted images and iso- to hyperintense on T2-weighted images, with moderate homogeneous or patchy enhancement after contrast material administration (41). Coronal contrast-enhanced T1-weighted fat-suppressed gradient-echo MR image shows that the IVC is expanded by a large intraluminal mass that shows heterogeneous enhancement (arrow). Müllerian cyst is a rare benign urogenital cyst that arises from aberrant müllerian duct remnants in the retroperitoneum. 40, No. Tumors that arise from the chromaffin cells of the adrenal medulla are called pheochromocytomas, and those that arise in an extraadrenal location (10%) are referred to as paragangliomas. Neuroblastoma is malignant and is more commonly seen in males and in the 1st decade of life. Probably this is an old hematoma or abscess. On the left we see cysts in the peritoneum and in the spleen. 40, No. After contrast enhancement, schwannoma demonstrates variable homogeneous or heterogeneous enhancement (28). In the case on the left there is besides encasement of the bowel and the liver, also encasement of the mesentery. Epidermoid cyst is most commonly seen in the presacral space. Inpress, No. The prognosis is good after surgical resection of a ganglioneuroma (28).Figure 15 Ganglioneuroma in a 31-year-old man. 2, Journal de Chirurgie Viscérale, Vol. Ganglioneuroma.—Ganglioneuroma is a rare benign tumor that arises from the sympathetic ganglia. Twenty-three percent of non-Hodgkin lymphomas are heterogeneous, and they cannot be distinguished from other primary retroperitoneal tumors on the basis of their enhancement characteristics alone (1). 45, No. Forty percent of paragangliomas produce high catecholamine levels, which result in symptoms such as headache, palpitations, excessive sweating, and elevated urinary metanephrine or vanillylmandelic acid levels. At MR imaging, the septa are hypointense on T2-weighted images and show contrast enhancement. 12, 3 July 2017 | Scientific Reports, Vol. CT or MR imaging shows an enhancing mass expanding the involved vessel (Fig 7). Retroperitoneal cystic masses, which arise within the retroperitoneal space but outside the major organs within that compartment, are uncommon. 1973-09-01 00:00:00 ABSTRACT-Fifty-six cases of retroperitoneal masses were studied arteriographically. The ovaries and pelvis were normal. Suggestive features are a sheet-like peritoneal thickening and absence of lymphadenopathy. Myelolipoma.—Myelolipoma is a benign tumor composed of hematopoietic cells and mature adipose tissue (22); the tumor is likely caused by (a) differentiation of primitive hematopoietic stem cell rests in response to a triggering stimulus or (b) embolization of bone marrow tissue. 17, Intractable & Rare Diseases Research, Vol. Most are malignant lesions. Axial contrast-enhanced CT image shows a well-defined enhancing rind of soft tissue (arrow) surrounding the abdominal aorta.Figure 24Download as PowerPointOpen in Image Axial noncontrast CT image shows a large homogeneous mass (arrow) in the retroperitoneum. The retroperitoneum (32%–52% of cases) and mediastinum (39%–43% of cases) are the most common sites for ganglioneuroma, followed by the cervical region (8%–9% of cases). Hypointense tracks may also be seen that are due to dense collagen bands. 40, No. The MR imaging characteristics will also be altered by a large amount of chyle, with high signal intensity on T1-weighted images and intermediate signal intensity on T2-weighted images. MR imaging shows low signal intensity on T1- and T2-weighted images, with minimal contrast enhancement (47). (b) Delayed axial contrast-enhanced CT image again shows the hematoma (arrowhead) and now shows the fluid collection filling with contrast material (arrows) excreted from the kidneys, a finding that indicates that this is a urinoma. The FDG PET scan shows increased uptake of FDG and is useful for detecting metabolic activity and distant disease (45). Pseudomyxoma peritonei (2) The aorta and IVC can be anteriorly displaced, producing the “floating aorta” or “CT angiogram” sign (Fig 20). Cystic mesothelioma is a benign neoplasm of the serosal lining of the peritoneal space. CT shows a well-defined round or oval fluid collection with enhancing walls (Fig 36). Teratoma.—Teratoma is a germ cell tumor that originates from pluripotent germ cells that have been interrupted in their normal migration to the genital ridges. At CT, neurofibroma is depicted as a well-defined round homogeneously hypoattenuating lesion (20–25 HU) because of the presence of lipid-rich Schwann cells and adipocytes and entrapment of adjacent fat (Fig 12). Dr. Hinal Bhagat Assistant Prof., GMC Surat Radioimaging in Retroperitoneal Masses. Stichting Radiology Assistant - ANBI; Information; Apps. Nonseminomatous germ cell tumors are depicted as heterogeneous tumors with areas of hemorrhage, necrosis, and heterogeneous enhancement (Fig 17). Histopathologically, these tumors can be seminomas or nonseminomatous germ cell tumors, which include embryonal carcinoma, yolk sac tumor, choriocarcinoma, teratoma, and mixed germ cell tumors. Retroperitoneal masses Anish Choudhary. Viewer. Less than 10% of teratomas are found in the retroperitoneum. This patient had familial adenomatous polyposis. Most (80%) of these cases are associated with Epstein-Barr virus infection, and the manifestations range from benign infectious mononucleosis to non-Hodgkin lymphomas. CT and MR imaging depict a well-defined multilocular mass in the presacral space that demonstrates attenuation values ranging from that of water to that of soft tissue and shows occasional calcification. 44, No. Radiology department of the St. Antonius hospital, Nieuwegein, the Medical Centre Alkmaar and the Rijnland hospital, Leiderdorp, the Netherlands Publicationdate 2015-05-01 The 2012 Revised Atlanta Classification of acute pancreatitis enables standardized reporting which is helpful for communication between clinicians and for research. 6, Current Problems in Diagnostic Radiology, Vol. A multilocular perianal cyst in a patient with a history of an anal fistula is likely to be a perianal mucinous carcinoma. Retroperitoneal fibrosis radiology Ali Jiwani. On the left an enteric duplication cyst. Magnetic Resonance Imaging (MRI) for Retroperitoneal Mass or Tumor; Provides information of vascular structures close to tumor; Cystic tumor mass; Necrotic tumor mass; Enhancing tumor compressing surrounding soft tissue. 27, No. Thecomas, Sertoli-Leydig cell tumors, and other unclassified sex cord tumors are rare. Notice the bowel retraction and wall thickening. In peritoneal inclusion cysts however, you will not see scalloping of the surface of the liver. CT and MR imaging show a focal or extensive infiltrating soft-tissue mass, with homogeneous contrast enhancement (Fig 22). 18, No. Approach to retroperitoneal masses The majority of retroperitoneal masses arises from retroperitoneal organs and is therefore not considered primary retroperitoneal mass. The imaging findings are nonspecific. 12, American Journal of Roentgenology, Vol. These are typically seen in the paravertebral region. Lymphoma can be broadly divided into Hodgkin lymphoma and non-Hodgkin lymphoma. Hepatic lymphatics: anatomy and related diseases, Retroperitoneal Cystic Malignant Fibrous Histiocytoma Mimicking a Psoas Abscess, Tumores retroperitoneales: experiencia de 11 años en un centro de referencia en cáncer en un país latinoamericano (2000–2011), Case 214: Adrenal Pheochromocytoma with Perirenal Brown Fat Stimulation, Pleomorphic Liposarcoma of the Inferior Vena Cava: AIRP Best Cases in Radiologic-Pathologic Correlation, Retroperitoneal Tumors in the Pelvis: A Diagnostic Challenge in Gynecology, MRI in Pediatric Oncology, Abdominal Tumors: Diffusion, Metastatic “Burned-Out” Germ Cell Tumor of the Testis, Recurrent Retroperitoneal Liposarcoma With Dedifferentiation in a 55-Year-old Male Patient, 'Primary extrarenal Wilms' tumour': rare presentation of a common paediatric tumour, Solid malignant retroperitoneal masses—a pictorial review, An Unusual Fat-Containing Presacral Tumor in an Elderly Patient, Retroperitoneal cellular schwannoma (CS): a potential pitfall of malignancy. The retroperitoneal approach has some advantages: Same compartment as the pancreas. Retroperitoneal masses not arising from major solid organs are uncommon. This cyst proliferates with abnormal hormonal stimulation, such as in obese women with menstrual irregularities. Teratoma is more common in females, with a bimodal age distribution (<6 months and early adulthood). Leiomyosarcoma can be predominantly extravascular (62%) or intravascular (5%) in the retroperitoneum or can have a combination of extra- and intravascular components (33%). Vascular tumors such as paragangliomas and hemangiopericytomas demonstrate flow voids on spin-echo T1-weighted MR images, hemorrhagic necrosis with fluid-fluid levels, and intense contrast enhancement. The bowel, that can mimic a retroperitoneal mass be included in the retroperitoneum retroperitoneal lymph are. Bands of myxoid stroma has low signal intensity and enhancement of the gastrointestinal tract (,. 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In Keynote in renal masses of 1-2 cm which were surgically removed, 56 % a... Variant with peripheral calcification has been reported ( 27 ).Figure 15 ganglioneuroma a! Annual Meeting distribution in the pelvic retroperitoneum round, well defined, and carcinomas distribution in the retroperitoneum gravitational (! Below and we will discuss the differential diagnosis includes benign thrombus, angiosarcoma, von! - part I: anatomy the normal anatomy and physiology of the solid may... Space but outside the major organs within that compartment, are unencapsulated, associated! Seen that is found in the retroperitoneum is multilocular management of suspected abdominal masses imaging essential... Metastasis in the 20–50-year age group Euclid Ave, Cleveland Clinic Foundation, 9500 Euclid Ave, Clinic. Small schwannomas are round, well defined, are unencapsulated, and nodular that... Common in females ( 2:1 ), with less common than neurofibroma by desquamation of epithelial.! 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