1. GI Cases 26-50

2. Case directory 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

3. Case 26

4. Omental infarction Case findings: Normal appendix
Case directory
Omental infarction
Case findings:
Normal appendix
Fatty lesion with hyper-attenuating streaks anterior to the cecum
Thickening of the peritoneum

5. Case 27

6. Axial T1WI
Axial T2WI with fat saturation

7. Axial T1 portal venous enhancement
Axial T1 delayed enhancement

8. Retractile mesenteritis
Inhomogeneous mass of soft-tissue density interspersed with areas of fat, arising from the small bowel mesentery
Moderate enhancement of the non-fatty aspects of the process
Mass surrounds mesenteric vessels and displaces adjacent small bowel loops
MR:
Mesenteric mass with irregular borders and low T1 SI
T2 intermediate signal intensity
Ascites in paracolic gutters and between mesenteric folds
PV enhancement: mild enhancement with a radiating pattern of strands and enhanced mesenteric vessels penetrating the lesion

9. Retractile mesenteritis
Also called: sclerosing mesenteritis, systemic nodular panniculitis, liposclerotic mesenteritis
Represents fibrous evolution of mesenteric panniculitis
Associated with:
SLE
Lymphoma
Gardner's syndrome
Thoracic mesothelioma
Retroperitoneal fibrosis

10. Retractile mesenteritis
MC presents as a single mass
Small bowel series:
Separation of loops, with kinking and angulation, suggesting a serosal process
CT:
Mesenteric mass with a variable amount of fat and soft tissue with radiating linear strands reflecting the fibrous reaction of the mesentery
May see calcifications
MR:
Low T1, low or intermediate T2
Mild and gradual contrast enhancement suggesting a fibrotic reaction

11. Retractile mesenteritis
Case directory
Retractile mesenteritis
DDX:
Liposarcoma: invasion of adjacent structures
Desmoid tumor:
Associated with Gardner's syndrome
MC occur in injured or surgically traumatized sites
Lymphoma
Carcinomatosis

12. Case 28

13. Peritoneal tuberculosis
Case directory
Peritoneal tuberculosis
Case findings:
Marked inhomogeneous thickening of the anterior peritoneal wall and SB
Marked enhancement
Mesenteric lymphadenopathy
Peritoneal infection can appear as:
Wet type
Dry type
Fibroadhesive type
Combination of above types
Wet type (this case): high-density ascitic fluid with exudative content and thickened mesentery

14. Case 29

15. Intramural hematoma Case findings: Etiology: anticoagulation
Case directory
Intramural hematoma
Case findings:
Thickening of jejunal loops
Etiology: anticoagulation
MC occurs in duodenum

16. Case 30

18. Emphysematous cholecystitis
Case findings:
Gas in GB wall that forms a low-attenuation ring outlining the gallbladder
Gas is also seen in the left intrahepatic and extrahepatic biliary ducts
DDX:
Emphysematous cholecystitis
Ascending cholangitis
Biliary-enteric fistula
Paraduodenal abscess
Periappendiceal abscess in malpositioned appendix
Gallbladder lipomatosis:  Plain-film mimmick of GB wall gas

19. Emphysematous cholecystitis
Case directory
Emphysematous cholecystitis
Acute infection of GB wall caused by gas-forming organisms
Unlike other biliary tract disorders, MC in men (65-70%)
Four proposed pathogenetic factors:
Vascular compromise
Gallstones
Impaired immune protection
Infection with gas-forming organisms

20. History of adenomatous polyposis and fundal gastric polyps
Case 31
History of adenomatous polyposis and fundal gastric polyps

22. Gardner’s syndrome (with desmoid tumors)
Case findings:
Multiple mesenteric and omental masses, which are ill-defined causing a tethered appearance to the mesentery
Bowel is displaced but not obstructed
Large pelvic mass
Mass in the soft tissues of the lower abdominal wall

23. Gardner’s syndrome (with desmoid tumors)
DDX tethered mesenteric folds:
Post-operative changes
Post-radiation changes
Desmoplastic reaction: carcinoid, peritoneal implants, leiomyosarcoma, lymphoma
DDX large solid pelvic mass in adult male:
Prostate / bladder / bowel neoplasm
Desmoid tumor
Malignant fibrous histiocytoma
Leiomyosarcoma
Neural tumor

24. Gardner’s syndrome Autosomal dominant Polyposis: Osteomas:
MC colon (100%), stomach (5%), SB (<5
Malignant transformation risk is 100%
Osteomas:
MC mandible, calvarium, maxilla
Soft tissue tumors:
Desmoid tumor
Sebaceous cysts
Neurofibroma, fibroma
Leiomyoma, lipomas
Surgical trauma predisposes Gardner patient to desmoid formation

25. AD= autosomal dominant, AR= autosomal recessive, NH= nonhereditary
Case directory
Polyposis syndromes
AD= autosomal dominant, AR= autosomal recessive, NH= nonhereditary

26. Case 32

27. Cecal and appendiceal adenocarcinoma
Case findings:
Asymmetric thickening of cecum and ascending colon
Inflammatory changes of posterior perirenal fascia extending into right colic gutter
Thickened appendix
DDX:
Appendicitis with phlegmon
Cecal malignancy with rupture and associated appendicitis 
Cecal diverticulitis
Crohn’s disease

28. Case directory
Appendiceal neoplasm
Rare to have appendiceal involvement with adenocarcinoma
Lymphoma and adenocarcinoma of appendix are less common
Appendiceal carcinoid:
90% of all appendiceal tumors are carcinoids
MC distal tip of the appendix
Produces a solid bulbous swelling 2 to 3 cm in diameter

29. Case 33

30. Malignant fibrous histiocytoma
Case findings:
Mass centered in right retroperitoneum that is separate from right kidney and adrenal gland
No clear fat plane is identified between the mass and the right psoas muscle
Enhances heterogeneously with areas of non-enhancement (necrosis)
DDX:
Malignant fibrous histiocytoma
Leiomyosarcoma
Lymphoma
Liposarcoma

31. Malignant fibrous histiocytoma
Case directory
Malignant fibrous histiocytoma
MC sarcoma in adults, 5th – 7th decades
Mesenchymal origin, potential to be in all organs:
MC lower extremities (50%)
Upper extremities (about 20%)
Abdominal cavity, retroperitoneum (20%)
> 5 cm at presentation
May erode into adjacent bony structures
Metastatic disease and local recurrence are common

32. Case 34

33. Hepatic angiomyolipoma
Case findings:
CT: mass in the posterior segment of the right hepatic lobe composed mostly of fatty tissue
MC solitary mass in liver
Hemorrhage uncommon complication

34. DDX fatty liver lesion Lipoma Hepatic adenoma Focal fatty infiltration
Case directory
DDX fatty liver lesion
Lipoma
Hepatic adenoma
Focal fatty infiltration
Angiomyolipoma
Metastasis (malignant teratoma, liposarcoma)
HCC with fatty metamorphosis
HCC: well differentiated, hypovascular
Angiomyolipoma: hypervascular

35. Case 35

36. Mesenteric panniculitis
Case directory
Mesenteric panniculitis
Case findings:
CT: hazy infiltration of the mesentery
Also called: sclerosing mesenteritis, mesenteric lipodystrophy, and liposclerotic mesenteritis
Benign inflammatory condition of the mesentery, which is frequently asymptomatic and self-limiting
MC left side of the abdomen along the orientation of the jejunal mesentery

37. Case 36

39. Pelvic lipomatosis Case findings: BE: CT:
Ascending curvature of the sigmoid colon
Elongation and deformity of the rectum by extrinsic compression
CT:
Deposits of fat in the perivesical and perirectal spaces causing extrinsic compression of the bladder, sigmoid, and rectum

40. Pelvic lipomatosis DDX tear-drop bladder: Pelvic lipomatosis
Case directory
Pelvic lipomatosis
DDX tear-drop bladder:
Pelvic lipomatosis
Hypertrophy of the iliopsoas muscles
Retroperitoneal fibrosis
Large pelvic abscess
Large hematoma, usually due to trauma or anticoagulation therapy
Collateral venous circulation from IVC obstruction
Large iliac artery aneurysms
Adenopathy from lymphoma, and prostatic carcinoma

41. Case 37