Cases

1. Cases Dr Ashokkumar II Year resident Dept of radiodiagnosis Date : 12-12-08 1

2. Case 1 • A recent immigrant Teenage male with headache, fever, mental status changes, and a seizure episode. • Not a known case of pulmonary Koch’s. • O/E: neck rigidity. 1

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4. D/D OF MULTIPLE RING ENHANCING LESIONS • Tuberculoma • Brain abscesses. • Neurocysticercosis. • Metastasis. 1

5. TUBERCULOMA • Irregular thick walls. • Perilesional oedema. • White matter hypodensities • Tiny punctate calcific foci BASAL EXUDATES 1

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7. NEUROCYSTICERCOSIS CALCIFIED NODULAR STAGE COLLOIDAL VESCICULAR STAGE VESCICULAR STAGE • Cystic lesion. • Scolex. • No focal oedama • no enhancement • Focal oedema • Ring enhancement. • Calcific foci • No focal oedema • No enhancement. 1

8. ABSCESS • Irregular walls, thicker at cortex & thinner at ependymal side. • Perilesional oedema. 1

9. METASTASIS • Known primary • Cortico medullary junction • Perilesional oedema. • No prediliction to a vascular territory 1

10. MULTIPLE RING ENHANCING LESIONS • Multiple satellite lesions. • Thin regular walls. • Similar shape • Mass effect • No mass effect • Variable size & • morphology. • Central scolex in • some of the lesions • Thick walled • GW matter • Mass effect • Known primary mets • Abscess • TB NCC 1

11. Case 2 • A 72-year-old man with a history of congestive heart failure, malignant hypertension, and peripheral and coronary vascular disease was admitted to the hospital 4 days after onset of acute dyspnea and lower-extremity edema. He underwent coronary catheterization; after this procedure, his serum creatinine levels increased from 1.6 to 5.9 mg/dL (141.4–521.6 µmol/L). • He was subsequently referred for renal and aortic magnetic resonance (MR) imaging to allow more comprehensive evaluation of renal and vascular disease. • Prior to admission, the patient had undergone coronary artery bypass graft placement for triple-vessel coronary artery disease (5 years previously) and right carotid endarterectomy (1 year previously). Pathologic specimens of the carotid artery showed dense fibrous tissue and chronic inflammation surrounding the vessel wall. 1

12. Transverse T1-weighted MR image (repetition time msec/echo time msec, 650/10) of the abdomen at the level of the kidneys. Abnormal slightly hypointense tissue (white arrows) is seen in the perirenal space (compared with the paravertebral muscles) and adjacent to the aorta (black arrow). 1

13. Figure 2. Transverse single-shot T2-weighted MR image (single shot/99.4) of the abdomen at the level of the kidneys. Abnormal tissue in the perirenal space has low signal intensity (thick white arrows). Tissue with similar characteristics surrounds the aorta (thin white arrow). 1

14. Figure 3. Transverse fat-saturated T2-weighted MR image (1767/91.6 [effective]) of the abdomen at the level of the kidneys. Abnormal hypointense tissue is seen in the perirenal space (thick white arrows). Tissue with similar characteristics surrounds the aorta (arrowhead) and the left renal artery (thin white arrow). 1

15. Figure 4. Transverse electrocardiographically gated double inversion-recovery fast spin-echo MR image (1000/18.4 [effective]) of the thorax shows slightly hypointense tissue (arrows) surrounding the aortic arch (compared with the paravertebral muscles). 1

16. Diagnosis : Multifocal Fibrosclerosis with Mediastinal-Retroperitoneal Involvement1 1

17. Discussion • Multifocal fibrosclerosis is a rare syndrome of unknown cause that is characterized by fibrosis involving multiple organ systems. • occurrence of different combinations of retroperitonealfibrosis (RPF), mediastinal fibrosis, Riedel thyroiditis, orbital pseudotumor, and sclerosing cholangitis • Depending on the involved organ systems, different clinical and radiologic manifestations are observed in patients with multifocal fibrosclerosis • symptoms of congestive heart failure and coronary artery disease were caused by atherosclerotic disease; atherosclerotic narrowing of the renal ostia also likely contributed to the patient’s renal failure and hypertension 1

18. Mediastinal fibrosis in multifocal fibrosclerosis is characterized by hypointense tissue on T1- and T2-weighted MR images in the mediastinum, especially around the aorta, • Mediastinal fibrosis can also be associated with superior vena cava obstruction, stenosis of the pulmonary veins, tracheal obstruction (eg, symptoms similar to asthma), esophageal stricture, pulmonary artery obstruction with cor pulmonale, and coronary artery occlusion . • Histologically, it has a similar appearance to that observed in patients with RPF 1

19. RPF • RPF is characterized by fibrous tissue proliferation surrounding the aorta and extending into periaortic tissue as a plaque-like infiltrative soft-tissue process • RPF is the most common manifestation of multifocal fibrosclerosis. • was a prominent component of multi-focal fibrosclerosis in the case presented, and • Renal failure may be profound, despite low-grade obstructive uropathy. • One proposed mechanism of obstruction is interference with ureteral peristaltic activity rather than mechanical obstruction. • Diagnosis of retroperitonealfibrosis is often suggested by imaging studies performed to enable the evaluation of nonspecific clinical signs and symptoms. 1

20. Excretoryurography : • Medial deviation and narrowing of the ureters near the lower lumbar spine demonstrated by represents a classic radiologic presentation of RPF Sonographic findings of RPF • consist of hydronephrosis and visualization of fibrotic tissue as a hypoechoic mass in the para-aortic region . CT • shows retroperitoneal plaque-like, infiltrative soft-tissue surrounding vessels and ureter. • The soft-tissue attenuation seen on CT scans is similar to that of muscle . • Enhancement is variable after intravenous administration of iodinated contrast material. 1

21. MR images : • show an infiltrative soft-tissue process with homogeneous low signal intensity compared with that of the adjacent psoas muscle seen on T1-weighted images • However, RPF can show moderate to high signal intensity on T2-weighted images, depending on the degree of associated inflammatory response. • Extensive inflammation early in the disease process results in increased T2 signal intensity. • MR imaging characteristics, however, are not specific for distinguishing benign from malignant cause. • Therefore, biopsy is essential to confirm the diagnosis. 1

22. CASE 3 • 49-year-old woman who had undergone radical hysterectomy for cervical cancer presented with retention of urine. 1

23. (a) Abdominal ultrasonographic image shows a well-defined cystic mass posterior to the urinary bladder (arrow and cursors). 1

24. Contrast-enhanced CT scan shows a large fluid collection with ring enhancement in the presacral space (arrow). The diagnosis was confirmed with CT-guided percutaneous aspiration and drainage revealed urine. 1

25. Diagnosis : Urinoma 1

26. Urinoma • Encapsulated collection of chronically extravasated urine. CAUSES : obstructive causes and nonobstructive (including abdominal trauma and injury to the collecting system during surgery or diagnostic instrumentation) can lead to urinary extravasation . • Urinoma is typically located in the perirenal space, it may be seen in other locations, possibly as a result of disruption of a part of the ureter inferior to the perirenal space. • Moderate or severe hydronephrosis is present in most patients . 1

27. CTFEATURES : • At unenhanced CT, urinoma usually manifests as a fluid collection with water attenuation. • However, the attenuation can increase progressively after intravenous administration of contrast material because contrast-enhanced urine enters the urinoma . • Percutaneous aspiration and drainage may allow confirmation of the diagnosis and treatment. 1

28. Retroperitoneal cystic lesions • Retroperitoneal cystic masses, which arise within the retroperitoneal space but outside the major organs within that compartment, are uncommon. • However, the widespread use of computed tomography (CT) for evaluating abdominal and retroperitoneal diseases has increased the detection rate for retroperitoneal cystic lesions 1

29. CT may provide important information regarding • lesion location, size, and shape; the presence and thickness of a wall; • Presence of septa, calcifications, or fat; and involvement of adjacent structures. • The most important clinical parameters include patient gender, age, symptoms, and clinical history. • Familiarity with the CT and clinical features of various retroperitonealcystic masses facilitates accurate diagnosis and treatment 1

30. Cystic lesions of retroperitoneum can be classified as • Nonneoplastic lesions • Pancreatic pseudocyst, • Nonpancreatic pseudocyst, • Lymphocele, • Urinoma, and • Hematoma Neoplastic lesions • cystic lymphangioma, • mucinous cystadenoma, • cystic teratoma, • cystic mesothelioma, • müllerian cyst, epidermoid cyst, • tailgut cyst, • bronchogenic cyst, • cystic change in solid neoplasms, • pseudomyxoma retroperitonei, and • perianal mucinous carcinoma. 1

31. Cystic Lymphangioma • Uncommon, congenital benign tumors and • Occur due to failure of the developing lymphatic tissue to establish normal communication with the remainder of the lymphatic system. • Most cystic lymphangiomas occur in the head or neck; a retroperitoneal location is unusual. • Unilocular or multilocular cysts containing clear or milky fluid and lined with a single layer of flattened endothelium . • Can occur anywhere in the perirenal, pararenal, or pelvic extraperitoneal spaces. • They may cross more than one compartment of the retroperitoneum. • M.C. in men and can occur at any age . 1

32. CT : • cystic lymphangioma typically appears as a large, thin-walled, multiseptate cystic mass. • Its attenuation values vary from that of fluid to that of fat . • An elongated shape and a crossing from one retroperitoneal compartment to an adjacent one are characteristic of the mass . • Rarely, cystic lymphangiomas may have wall calcification. • Surgical excision is the treatment of choice. 1

33. Contrast material-enhanced CT scan shows a low-attenuation mass in the right anterior pararenal space (arrow). 1

34. Retroperitonealcystic lymphangioma in a 41-year-old man. Contrast-enhanced CT scans show a lobulated cystic mass (thick arrows) in the anterior pararenal space. The third portion of the duodenum is compressed by the mass. 1

35. Retroperitonealcystic lymphangioma in a 41-year-old man. Contrast-enhanced CT scans show a lobulated cystic mass (thick arrows) with tiny mural calcifications (thin arrow ) in the anterior pararenal space. The third portion of the duodenum is compressed by the mass. 1

36. Mucinous Cystadenoma • Primary mucinous cystadenomas are rare retroperitonealcysticlesions that occur in women with normal ovaries. • Early diagnosis of primary mucinous cystadenomas is important because of their malignant potential . • CT :Primary retroperitoneal mucinous cystadenoma usually manifests as a homogeneous, unilocular cystic mass . 1

37. D/D • Cystic mesothelioma, • Cystic lymphangioma, and • Nonpancreatic pseudocyst is difficult. • Exploratory laparotomy with complete excision of the cyst is usually indicated for both diagnosis and treatment. 1

38. Retroperitoneal mucinous cystadenoma in a 41-year-old woman. (a) Contrast-enhanced CT scan shows a homogeneously hypoattenuating mass in the right anterior pararenal space (arrow). 1

39. Retroperitoneal mucinous cystadenoma in a 56-year-old woman. Contrast-enhanced CT scan shows a homogeneously hypoattenuating mass in the right retroperitoneal space (arrow). The ascending colon is displaced anteriorly. 1

40. Cystic Teratoma • Retroperitonealcystic teratomas are cystic tumors composed of well-differentiated derivations from at least two of the three germ layers (ectoderm, mesoderm, endoderm). • M.C. : female, and the tumor is commonly diagnosed in newborns, who are usually asymptomatic . • A cystic teratoma is likely to be benign, whereas a • solid teratoma is likely to be malignant . • CT : a mature teratoma of the retroperitoneum manifests as a complex mass containing a well-circumscribed fluid component, adipose tissue, and calcification . • Presence of hypoattenuating fat within the cyst is considered highly suggestive of cystic teratoma. • With the presence of calcifications in the cyst wall, cystic teratoma is even more likely 1

41. Cystic teratoma in a 3-year-old girl. (a) Contrast-enhanced CT scan shows a well-defined hypoattenuating mass with internal septa and calcifications in the right anterior pararenal space (arrow) 1

42. Cystic Mesothelioma • Rare benign neoplasms with a mesothelial origin that originate in the serous lining of the pleural, pericardial, or peritoneal space . • Cystic mesothelioma usually occurs in the surfaces of the pelvic viscera but may occur in the retroperitoneum. • Unlike malignant mesothelioma, cystic mesothelioma is not related to prior asbestos exposure. • It does not metastasize but may recur locally and occurs more frequently in women. • Abdominal pain is the most common symptom. 1

43. CT ; • Unilocular or multilocular thin-walled cyst containing watery secretions. • Usually appear as nonspecific, thin-walled, multilocular cysticlesions . • They may be radiologically indistinguishable from lymphangiomas and other retroperitoneal cysts. 1

44. Müllerian Cyst • Müllerian cyst is a subtype of urogenital cyst . . • Urogenital cysts arise from vestiges of the embryonic urogenital apparatus and can be classified into pronephric, mesonephric, metanephric, and müllerian types based on their embryonic lines. • Müllerian cyst of the retroperitoneum is an extremely rare disease. • It is a benign condition that can be cured with surgical resection. • Müllerian cyst of the retroperitoneum occurs in women from 19 to 47 years of age . 1

45. CT : • Müllerian cyst manifests as a unilocular or multilocular thin-walled cyst containing clear fluid. D/D • cystic mesothelioma and • cystic lymphangioma . • Clinical history may be useful for differentiating müllerian cyst from other retroperitonealcystic masses. • Müllerian cyst occurs in obese patients with menstrual irregularities. 1

46. Figure 6a.  Müllerian cyst in a 57-year-old woman. (a) Contrast-enhanced CT scan shows a well-defined cystic mass in the left retroperitoneal space (arrow). 1

47. Epidermoid Cyst • Rare congenital lesions of ectodermal origin and can occur anywhere from the head to the foot. • Epidermoid cysts that develop in the presacral space are quite rare, usually occurring in middle-aged women . • Most patients are asymptomatic, they may present with symptoms resulting from local mass effect (eg, constipation, lower abdominal pain) . 1

48. CT : • Appear as thin-walled, unilocular cystic masses with fluid attenuation . • These findings are not specific enough to allow differentiation of epidermoid cysts from other retroperitonealcystic masses. However, the location of epidermoid cysts can be helpful in making the diagnosis because these lesions usually occur at the presacral retroperitoneal space . 1

49. Contrast-enhanced CT scan shows a well-defined hypoattenuating mass in the pelvic retroperitoneum (thick arrow). The rectum is anteriorly displaced (thin arrow). 1

50. Tailgut Cyst • Rare congenital multicysticlesions that arise from vestiges of the embryonic hindgut and occur between the rectum and sacrum. • These cysts are typically lined by several different types of epithelium . • M .C. in women and usually appears in middle age. 1