Extranodal lymphoma in the abdomen: Spectrum of imaging findings

Transcription

1 Extranodal lymphoma in the abdomen: Spectrum of imaging findings Poster No.: C-0623 Congress: ECR 2014 Type: Educational Exhibit Authors: N. Bystrická, H. Poláková, J. Sykora; Bratislava/SK Keywords: Lymphoma, Cancer, Staging, Diagnostic procedure, CT, Oncology, Hematologic, Abdomen DOI: /ecr2014/C-0623 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 38

2 Learning objectives # To illustrate the spectrum of imaging findings of extranodal lymphoma in the abdominal region. # To discuss the differential diagnosis of lymphomatous involvement of the different abdominal structures. # To review the key imaging findings that enable the differentiation of extranodal lymphoma from other benign and malignant diseases. Background The term extranodal lymphoma refers to Hodgkin disease and Non Hodgkin lymphomas in sites other than the lymph nodes, thymus, tonsils, and pharyngeal lymphatic ring (Waldeyer'stonsillar ring). In HD, splenic involvement is considered nodal, whereas in NHL it is considered extra nodal. The incidence of extranodal disease is higher in NHL than in HD. It is also more common in patients with recurrent disease, AIDS related lymphoma and post-transplant lymphoproliferative disorder. Secondary involvement of extranodal tissues as a part of generalized disease is much more common than primary extranodal lymphoma, in which the lymphomatous involvement is confined to a single organ and immediately adjacent lymph nodes. In the abdomen lymphomas may affect different extranodal structures, including both the solid organs and the hollow viscus of the digestive tract (Fig. 1 on page 3). The purpose of this educational exhibit is to review the spectrum of imaging findings of extranodal lymphoma in the abdomen with the emphasis on CT manifestations. Abbreviations: HD - Hodgkin disease NHL - Non Hodgkin lymphoma CT - computed tomography Page 2 of 38

3 Cor MPR - coronal multiplanar reconstruction Sag MPR - sagittal multiplanar reconstruction DDx - differential diagnosis HCC - hepatocellular carcinoma MTS - metastasis RCC - renal cell carcinoma AML - angiomyolipoma GI - gastrointestinal MFH - malignant fibrous histiocytoma GIST - gastrointestinal stromal tumor Images for this section: Page 3 of 38

4 Fig. 1: Extranodal lymphoma in the abdomen Page 4 of 38

5 Findings and procedure details 1. Hepatic involvement (Fig. 2 on page 12) a) Diffuse infiltration Imaging appearance: The sensitivity of CT in the detection of hepatic involvement is low, because the liver usually has a homogeneous appearance. In some cases the liver texture is noted to be irregular, and the appearance is more suggestive of benign parenchymal disease (e.g. fatty infiltration). Hepatomegaly may be present but is nonspecific. Differential diagnosis: fatty infiltration, parenchymal disease b) Multiple nodules Imaging appearance: Multifocal hepatic involvement appears as circumscribed, homogeneous nodules that are low attenuation on contrast enhanced CT. The lesions may vary in size but typically are 1-5cm in diameter. Dominant liver mass is atypical in secondary lymphoma, but is characteristic of primary lymphoma (Fig. 3 on page 12). Differential diagnosis: hypovascular metastases (such as carcinoma, melanoma) (Fig. 5 on page 14a) disseminated fungal abscesses c) Solitary mass Imaging appearance: The tumor is typically homogeneous and hypovascular, with subtle enhancement after intravenous contrast material administration. Occasionally, central necrosis may occur and produce heterogeneous appearance (Fig. 4 on page 13). Calcifications are. Page 5 of 38

6 Differential diagnosis: hypovascular metastasis (Fig. 5 on page 14b) cholangiocarcinoma - capsular retraction, delayed enhancement (Fig. 5 on page 14c) hepatocellular carcinoma - hypervascularity with washout, late enhancing pseudocapsule, venous invasion (Fig. 5 on page 14d) 2. Splenic involvement (Fig. 6 on page 15) a) Diffuse infiltration Imaging appearance: The imaging appearance of the spleen is usually normal, however, ill-defined hypoenhancing foci with diameters of less than 1cm may be present. Splenomegaly may occur, but this finding has a very low sensitivity and specificity. Marked splenomegaly, however, almost always indicates splenic lymphoma (Fig. 7 on page 16a). Differential diagnosis: reactive splenomegaly - occurs in about 30% of patients in the absence of lymphoma deposits normal inhomogeneous enhancement during the early phase of bolus injection of contrast material angiosarcoma - enlarged spleen in which the normal parenchyma is almost entirely replaced by heterogeneously attenuating mass or masses (Fig. 7 on page 16b). b) Multiple nodules Imaging appearance: Multifocal splenic lymphoma appears as multiple hypoattenuating nodules on contrastenhanced CT. Nodules are usually larger than 1cm in diameter (Fig. 8 on page 17a). Differential diagnosis: hypovascular metastases (Fig. 8 on page 17b) Page 6 of 38

7 fungal microabscesses - tend to be smaller (may range from 2-20mm); occur in the absence of lymphadenopathy; may affect spleen, liver and other solid organs; tend to show heterogeneous enhancement; typically occur in patients with neutropenia and fever c) Solitary mass Imaging appearance: CT demonstrates hypoattenuating mass with reduced enhancement compared with normal splenic tissue (Fig. 8 on page 17c). Differential diagnosis: inflammatory pseudotumor, granuloma (Fig. 8 on page 17d) angiosarcoma 3. Renal involvement a) Multiple masses Imaging appearance: The involvement is usually bilateral but may also be unilateral. Lymphomatous masses are typically homogeneous, isodense or slightly hyperdense to normal renal parenchyma on unenhanced CT and hypodense on contrast enhanced CT (Fig. 9 on page 18). Necrosis and calcifications are rare. Differential diagnosis: hypovascular metastases acute pyelonephritis, abscesses septic emboli, renal infarcts b) Solitary mass Imaging appearance: Page 7 of 38

8 Patients may present with a solitary homogeneous hypovascular mass that shows minimal enhancement following intravenous administration of contrast material (Fig. 10 on page 19). Cystic appearance or presence of associated thrombus in the renal vein is highly unusual (Fig. 16 on page 25 a,d). Differential diagnosis: clear cell RCC - hyperenhancing, heterogeneous, thrombosis of renal vein or cystic components may be present (Fig. 16 on page 25c) papillary and chromophobe RCC - tend to be hypovascular hypovascular metastasis (Fig. 16 on page 25e) c) Diffuse infiltration Imaging appearance: Infiltrative involvement is almost always bilateral and results in nephromegaly with patchy poorly defined hypoenhancing areas of infiltrative disease. The renal contour remains preserved (Fig. 11 on page 20). Rarely, large reniform mass infiltrates and destroys the entire organ and manifests as a nonfunctioning kidney. Differential diagnosis: transitional cell carcinoma collecting duct or medullary RCC d) Perirenal disease Imaging appearance: At CT, soft tissue nodules or homogeneous rinds of soft tissue are seen partly or completely surrounding the kidney without parenchymal compression or functional impairment (Fig. 12 on page 21,Fig. 13 on page 22). Differential diagnosis: retroperitoneal neoplasm metastasis to perirenal space (Fig. 16 on page 25f) Page 8 of 38

9 benign conditions - hematoma (Fig. 16 on page 25g), urinoma, pancreatitis e) Contiguous retroperitoneal extension Imaging appearance: Bulky retroperitoneal disease may cause renal involvement by extension into the renal hilum, sinus, or parenchyma. At imaging, large retroperitoneal mass is seen enveloping the renal vasculature and invading the renal hilum (Fig. 14 on page 23). Hydronephrosis due to entrapment of the ureters is common, however, renal arteries and veins remain patent. Differential diagnosis: retroperitoneal fibrosis f) Renal sinus involvement Imaging appearance: At imaging, the renal sinus is replaced by a homogeneous soft tissue mass (Fig. 15 on page 24). Vascular encasement and mild hydronephrosis is common. Differential diagnosis: transitional cell carcinoma 4. Pancreatic involvement (Fig. 17 on page 26) a) Diffuse involvement Imaging appearance: Infiltrative lymphomatous disease manifests as diffuse glandular enlargement. The affected gland may have slightly lower attenuation on unenhanced CT scans and show diffusely reduced, homogeneous enhancement after intravenous contrast material administration (Fig. 18 on page 27b). Pancreatic fat stranding may be present. Differential diagnosis: Page 9 of 38

10 pancreatitis b) Focal involvement Imaging appearance: Focal pancreatic lymphoma manifests as a well circumscribed homogeneous mass (Fig. 18 on page 27a). Although bile duct obstruction may occur, moderate to severe dilatation of the main pancreatic duct is uncommon. Vascular invasion, pancreatic atrophy distal to the tumor, and calcification and necrosis are also unusual. Differential diagnosis: metastasis to pancreas or to pancreaticoduodenal nodes (Fig. 18 on page 27c) pancreatic carcinoma - heterogeneous enhancement, pancreatic duct dilatation, pancreatic tail atrophy, and vascular invasion are common; lymphadenopathy below the level of the renal veins is very rare (Fig. 18 on page 27d) focal pancreatitis 5. Gastrointestinal involvement Imaging appearance: a) Diffuse infiltration Diffuse infiltrative form of gastrointestinal lymphoma appears as circumferential wall thickening of the gastric or intestinal wall. The tumor is usually hypo- or isoattenuating and hypoenhancing in comparison with normal bowel. Lesions may be solitary or multiple. The surrounding fat planes are usually preserved (Fig. 19 on page 28). Diffuse infiltration may lead to destruction of the muscularis propria and autonomic plexus. The involved segment becomes nonperistaltic, circumferentially dilates, and assumes aneurysmal appearance. The tumor may excavate the mesentery, producing a cavitated mass. c) Focal polypoid/nodular form Focal gastrointestinal involvement manifests as solitary or multiple hypoenhancing intramural masses or nodular intraluminal filling defects. The tumors are usually Page 10 of 38

11 homogeneous (Fig. 20 on page 29). Larger lesions, however, may contain areas of hemorrhage or ischemia. d) Ulcerative form Single or multiple ulcers of varying size are present (Fig. 21 on page 30). Complications: perforation - uncommon, more likely after chemo- or radiotherapy fistulation - may mimic Crohn's disease obstruction - uncommon because of absent desmoplastic reaction Differential diagnosis: gastrointestinal adenocarcinoma - may present with infiltrative, polypoid or ulcerative patterns; more likely to cause obstruction; more likely to infiltrate into adjacent structures (Fig. 22 on page 31, Fig. 23 on page 32b, Fig. 25 on page 34b) leiomyoma / leiomyosarcoma / GIST (Fig. 23 on page 32a). metastatic disease (especially melanoma) (Fig. 24 on page 33b,c). inflammatory bowel disease, neutropenic colitis 6. Peritoneal involvement Imaging appearance The patterns of peritoneal lymphomatosis include peritoneal thickening with contrast enhancement, discrete nodules, diffuse infiltrative mass, and ascites (Fig. 26 on page 35a). Differential diagnosis primary tumors of the peritoneum - peritoneal mesothelioma (Fig. 26 on page 35b) secondary peritoneal involvement - carcinomatosis, sarcomatosis (Fig. 26 on page 35c) non neoplastic diseases - tuberculous peritonitis Page 11 of 38

12 Images for this section: Fig. 2: Schematic shows characteristic CT features of lymphomatous disease in the liver. The patterns of involvement include diffuse infiltration, multiple nodules and solitary masses. Page 12 of 38

13 Fig. 3: a) Hodgkin disease in a 27-year-old woman. Axial CT scan and Cor MPR demonstrate multiple inconspicuous similar-sized nodules throughout the liver (red arrowheads). Retroperitoneal lymphadenopathy (*) and splenic involvement (purple arrowheads) are also present. b) Diffuse large B-cell lymphoma in a 44-year-old man. Axial CT scan and Cor MPR demonstrate multiple low-attenuation lesions within the liver with a dominant mass in the left lobe (red arrowhead). Splenic involvement is also present (purple arrowheads). Page 13 of 38

14 Fig. 4: a) Diffuse large B-cell lymphoma in a 53-year-old woman. Axial CT scan and Cor MPR demonstrate an 8cm solitary mass in the left lobe of the liver (red arrowhead). The mass is hypovascular and homogeneous. Gastric involvement is also present (orange arrowhead). b) Primary diffuse large B-cell lymphoma of the liver in an 82-year-old man. Axial CT scan and Cor MPR demonstrate a 14cm solitary mass in the left lobe of the liver (red arrowhead). The mass contains a large area of central necrosis. Page 14 of 38

15 Fig. 5: a) Metastatic breast carcinoma in a 65-year-old woman. Axial CT scan demonstrates multiple low-attenuation lesions within the liver (arrowheads). b) Metastatic GIST in a 72-year-old woman. Axial CT scan demonstrates solitary low-attenuation mass in the right lobe of the liver (arrowheads). c) Peripheral cholangiocellular carcinoma in a 51-year-old woman. Axial CT scan demonstrates large hypovascular lesion bridging the right and left hepatic lobes (arrowhead). d) Hepatocellular carcinoma in a 69-yearold man. Axial CT scan in the arterial (left) and portal venous phase (right) demonstrate a mass in the right lobe of the liver (arrowhead). Small hyperenhancing foci within the lesion can be seen in the arterial phase. Page 15 of 38

16 Fig. 6: Schematic shows characteristic CT features of lymphomatous disease in the spleen. The patterns of involvement include diffuse infiltration, multiple nodules and solitary masses. Page 16 of 38

17 Fig. 7: a) Splenic lymphoma with villous lymphocytes in an 86-year-old woman. Axial CT scan and Cor MPR demonstrate marked splenomegaly (*). b) Splenic angiosarcoma in a 54-year-old man. Axial CT scan and Cor MPR demonstrate marked splenomegaly (*). The normal parenchyma is almost entirely replaced by tumor. The spleen shows heterogeneous attenuation due to presence of necrosis, hemorrhage and small hypervascular foci. Liver metastases are also noted (red arrowheads). Page 17 of 38

18 Fig. 8: a) Diffuse large B-cell lymphoma in a 51-year-old man. Axial CT scan demonstrates well-defined, hypoattenuating, hypoenhancing lesions in the spleen (arrowheads). b) Metastatic melanoma in a 63-year-old man. Axial CT scan demonstrates well-defined, hypoattenuating, hypoenhancing lesions in the spleen (arrowheads) and in the liver. c) Diffuse large B-cell lymphoma in a 30-year-old man. Axial CT scan demonstrates a large, hypoattenuating, homogeneous round mass in the spleen (*). d) Splenic granulomas in a 71-year-old man. Axial CT scan demonstrates two demonstrates well-defined, hypoattenuating, heterogeneous masses in the spleen (arrowheads). Central regions of hypoattenuation represent necrosis. Page 18 of 38

19 Fig. 9: Illustration (a) shows the characteristic CT appearance of multiple masses in renal lymphoma. Axial CT image (b) and Cor MPR CT scan (c) demonstrate bilateral renal masses in a patient with diffuse large B-cell lymphoma. Multifocal splenic involvement is also present (S). Page 19 of 38

20 Fig. 10: Illustration (a) shows the characteristic CT appearance of a solitary renal lymphomatous mass. Axial CT image (b) and Cor and Sag MPR CT scan (c,d) demonstrate solitary mass (yellow arrowhead) in the right kidney in a patient with diffuse large B-cell lymphoma. A solitary pancreatic lesion (green arrowhead) is also present. Page 20 of 38

21 Fig. 11: Illustration (a) shows the characteristic CT appearance of renal lymphoma manifesting as infiltrative disease. Axial CT image (b) and Cor and Sag MPR CT scan (c,d) demonstrate patchy tumor infiltration within the kidneys in a patient with diffuse large B-cell lymphoma. The kidneys have retained their normal contour. Page 21 of 38

22 Fig. 12: Illustration (a) shows the characteristic CT appearance of perirenal lymphoma manifesting as a soft tissue rind, which surrounds but does not destroy the underlying kidney. Axial non contrast CT image (b), axial images in corticomedullary and nephrographic phase (c, d) and Cor MPR CT scan (e) demonstrate a perirenal soft tissue rind enveloping the left kidney in a patient with non-hodgkin lymphoma (arrowheads). Page 22 of 38

23 Fig. 13: Illustration (a) shows the characteristic CT appearance of perirenal lymphoma manifesting as soft tissue nodules. Axial CT image (b) and Cor MPR CT scan (c) demonstrate bilateral soft tissue nodules (arrowheads) in the perirenal space in a patient with Burkitt's lymphoma. Mesenteric lymphadenopathy is also present (*). Page 23 of 38

24 Fig. 14: Illustration (a) shows the characteristic CT appearance of lymphoma manifesting as continuous retroperitoneal extension. Axial CT image (b) and Cor and Sag MPR CT scan (c, d) demonstrate a large retroperitoneal mass (arrowheads) enveloping the IVC and invading the right renal sinus and perirenal fat in a patient with diffuse large B-cell lymphoma. Page 24 of 38

25 Fig. 15: Illustration (a) shows the characteristic CT appearance of renal sinus involvement. Axial CT image (b) and Cor MPR CT scan (c) demonstrate homogeneous soft tissue masses (arrowheads) in the both renal sinuses in a patient with follicular lymphoma. Retroperitoneal lymphadenopathy is also present. Note the lack of significant hydronephrosis. Page 25 of 38

26 Fig. 16: Imaging features such as cystic content (a), fatty components (b), hypervascular portions (c) or renal vein thrombosis (d) are not suggestive of renal lymphoma. Hypovascular renal (e) or perirenal (f) metastases may mimic lymphoma. Hematoma (g) is suspected in a patient with history of trauma. Page 26 of 38

27 Fig. 17: Schematic shows characteristic CT features of lymphomatous disease in the pancreas. The patterns of involvement include diffuse infiltration and focal masses. Imaging features of pancreatic carcinoma are also displayed. Page 27 of 38

28 Fig. 18: a) Non Hodgkin lymphoma in a 58-year-old woman. Axial CT scan shows hypoattenuating, hypoenhancing mass in the pancreatic tail (arrowhead). b) Follicular lymphoma in a 59-year-old woman. Axial CT scan shows diffuse enlargement of the pancreas (arrowheads). Contrast enhancement is diffusely reduced, yet homogeneous. c) Metastatic melanoma in a 55-year-old man. Axial CT scan shows multiple hypoenhancing nodular masses in the pancreas (arrowheads). Metastases in the liver and adrenals are also present. d) Pancreatic carcinoma in a 61-year-old woman. Axial CT scan shows hypoattenuating mass in the pancreatic head (arrowhead). The mass demonstrates heterogeneous enhancement. Page 28 of 38

29 Fig. 19: Schematic shows characteristic CT features of lymphoma presenting as a diffuse infiltration of gastrointestinal tract. Axial CT image (a) and Cor MPR CT scan (b) demonstrate diffuse concentric thickening of the gastric wall involving the fundus and proximal body (full arrowheads) in a patient with mantle cell lymphoma. Coronary scan also shows hypoenhancing mass in the cecum (empty arrowheads). Page 29 of 38

30 Fig. 20: Schematic shows characteristic CT features of gastrointestinal lymphoma presenting as a mass or polyp. Axial CT images (a, b) at two different levels demonstrate intraluminal homogeneous soft-tissue masses in the stomach (arrowheads) in a patient with lymphoma. Page 30 of 38

31 Fig. 21: Schematic shows characteristic CT features of gastrointestinal lymphoma presenting as an ulcerative mass. Axial CT image (a) and Cor MPR CT scan (b) demonstrate thickening of the gastric wall with ulceration in the body of the stomach (arrowhead) in a patient with diffuse large B-cell lymphoma. Page 31 of 38

32 Fig. 22: Schematic shows characteristic CT features of gastrointestinal lymphoma and carcinoma. Page 32 of 38

33 Fig. 23: a) GIST in a 69-year-old man. Axial CT scan and Cor MPR demonstrate wellcircumscribed intraluminal mass in the stomach (arrowhead). b) Gastric adenocarcinoma in a 70-year-old man with history of NHL and lung cancer. Axial CT scan and Cor MPR demonstrate thickening of the gastric wall (orange arrowheads). Liver metastasis is also present (red arrowhead). Page 33 of 38

34 Fig. 24: a) T-cell non-hodgkin lymphoma in a 58-year-old woman. Axial CT scan and Cor MPR demonstrate marked circumferential thickening and aneurysmal dilatation of small bowel loop (arrowheads). b) Metastatic melanoma in a 39-year-old man. Axial CT scan and Cor MPR demonstrate thickened small bowel loops (arrowheads) with aneurysmal dilatation. c) Metastatic malignant fibrous histiocytoma of the lung in a 62-year-old man. Axial CT scan and Cor MPR demonstrate thickened small bowel loops (arrowheads) with aneurysmal dilatation. Page 34 of 38

35 Fig. 25: a) Diffuse large B-cell lymphoma in an 83-year-old woman. Axial CT scan and Cor MPR demonstrate marked circumferential wall thickening involving the ascending colon (arrowheads) with preservation of pericolic fat plane. Bulky lymphadenopathy is also present (*). b) Colon cancer in a 45-year-old man. Axial CT scan and Cor MPR demonstrate moderate circumferential wall thickening and luminal narrowing involving the descending colon (orange arrowheads). There is stranding of surrounding fat, a finding compatible with local tumor extension. Adjacent lymphadenopathy (white arrowheads) turned out to be reactive on subsequent histology. Page 35 of 38

36 Fig. 26: a) Diffuse large B-cell lymphoma in a 54-year-old woman. Axial CT scan and Cor MPR demonstrate omental infiltration (full arrowheads), diffuse linear peritoneal thickening (empty arrowhead) and ascites (*). b) Malignant peritoneal mesothelioma in a 51-year-old man. Axial CT scan and Cor MPR demonstrate omental cake (full arrowheads), diffuse linear peritoneal thickening (empty arrowhead) and ascites (*). c) Carcinomatosis in a 60-year-old woman. Axial CT scan and Cor MPR demonstrate omental cake (full arrowheads), diffuse linear peritoneal thickening (empty arrowhead) and ascites (*). Page 36 of 38

37 Conclusion Abdominal organs are a common site for extranodal spread of lymphoma. The imaging features of lymphomatous involvement, however, may be nonspecific and may mimic a broad spectrum of benign and malignant conditions. It is vital for the radiologist to be aware of the range of imaging appearance of lymphoma, since misinterpretation of the imaging findings can lead to delayed diagnosis or inappropriate staging, both resulting in incorrect management of the disease. Personal information MUDr. Nadežda Bystrická, MUDr. Juraj Sýkora, MUDr. Hana Poláková Department of radiology Národný Onkologický Ústav Klenová 1, Bratislava Slovakia nadja.bys@post.sk References Fishman EK, Kuhlman JE, Jones RJ. CT of lymphoma: spectrum of disease. Radiographics 1991; 11(4): Leite NP, Kased N, Hanna RF, et al. Cross-sectional imaging of extranodal involvement in abdominopelvic lymphoproliferative malignancies. RadioGraphics 2007; 27: Thomas A, Vaidhyanath R, Kirke R, Rajesh A. Extranodal lymphoma from head to toe: part 2, the trunk andextremities. AJR 2011; 197: Lee WK, Lau EW, Duddalwar VA, Stanley AJ, Ho YY. Abdominal manifestations of extranodal lymphoma: spectrum of imaging findings. AJR 2008;191(1): Page 37 of 38

38 Guermazi A, Brice P, de Kerviler E, et al. Extranodal Hodgkin disease: spectrum of disease. RadioGraphics 2001; 21: Sheth S, Ali S, Fishman E. Imaging of renal lymphoma: patterns of disease with pathologic correlation. RadioGraphics 2006; 26: Urban BA, Fishman EK. Renal lymphoma: CT patterns with emphasis on helical CT. RadioGraphics 2000;20(1): Sheeran SR, Sussman SK. Renal Lymphoma: Spectrum of CT Findings and Potential Mimics. AJR 1998; 171: Ghai S, Pattison J, Ghai S, O'Malley ME, Khalili K, Stephens M. Primary gastrointestinal lymphoma: spectrum of imaging findings with pathologic correlation. RadioGraphics 2007; 27: Warshauer DM, Hall HL. Solitary splenic lesions. Semin Ultrasound CT MR 2006 Oct;27(5): Page 38 of 38