Small Bowel Flashcards
DDx for smooth surfaced filling defect in jejunum
GIST Hemangioma Lipoma Metastasis Lymphoma
Where in the small bowel do lipoma usually occur? What is a key differentiating feature?
Distal in the small bowel
Compressibility!
What is the difference between lipoma and liposarcoma?
Lipoma will be homogeneously fat
Liposarcoma will have a soft tissue component
What is the DDx for multiple small bowel lesions on SBFT?
Lymphoma, Polyposis, Hemangioma, Neurofibroma, Metastases
Where do hemangiomas usually occur?
What syndromes have an increased incidence?
Jejunum
Turner
Tuberous sclerosis
Blue rubber nevus
Rendu-osler-weber
What is CT enterography?
IV contrast enhances the bowel wall
Water attenuation luminal contrast enhances the lumen
How do hemangiomas present on CT?
CAN have calcifications
Small tufts of enhancement within the bowel wall
What two syndromes are associated with diffuse hemangiomatosis
Klipper-trenauny-Weber (varicose veins, cutaneous hemangiomas, soft tissue/bone hypertrophy)
Maffuic (enchondromas, subcutaneous cavernous hemangiomas)
Cauliflower like grouped polyps in the jejunum in a
Peutz Jeughers (Hamartomatous polyps)
What cells do carcinoid tumors arise from? What do they produce? What size does malignant transformation occur? Where are they found in the small bowel?
What is the radiographic appearance?
Kulchitsky cells (APUD), usually 2-3cm
Serotonin
>1cm
Distal small bowel, within 2 feet of ileocecal valve
Cause a fibrotic reaction leading to kinking of the bowel with obstruction.
Starburst appearance with linear stranding radiating from a central mesenteric mass with calcification indicates what?
Metastatic carcinoid to the small bowel
How do carcinoid mets to the liver present?
Hypervascular mass with central necrosis
Who is at risk of small bowel lymphoma?
AIDS
Celiac disease
Crohns
Lupus
Which lymphoma is most common in the small bowel?
NHL
What are the 4 classifications of small bowel lymphoma?
Which is most common?
Multiple nodules - most common, can cross IC valve
Infiltrating
Polypoid - can be “pseudopedunculated”
Endo-exoenteric
DDx for a focal segment of small bowel with smooth mucosa and loss of folds.
Differentiate them
Ischemia - will have narrowed lumen
Amyloidosis - may cause fold thickening
Lymphoma - wont have associated fibrosis, thus causing dilation (vs narrowing with ischemia)
Differentiate small bowel lymphoma vs ischemia
Ischemia will cause lumenal narrowing
Differentiate hodgkins vs nonhodgkins in the small bowel
Hodgkins will incite a desmoplastic reaction, causing luminal narrowing
What type of lymphoma in AIDS patients?
B-cell lymphoma
What helps to differentiate malignant GIST vs lymphomas?
adenopathy
Where is primary adenocarcinoma most commonly found in the small bowel? What is a known risk factors?
Proximal, duodenum
Adult celiac disease
How do malignant GIST spread?
Hematogenous and peritoneal spread
How common is small bowel mets in metastatic melanoma?
50% at autopsy
Bulky intraluminal mass in the retroperitoneal duodenum suggests what?
Invasive renal cell carcinoma
Large cavitated mass devoid of mucosal markings with destruction of the bowel wall can be seen with what 3 entities?
Lymphoma, malignant GIST, colon cancer mets
Where are the 3 most common sites of intraperitoneal seeding? How does it present radiographically?
Pouch of douglas, ileocecal region, superior aspect of sigmoid
Displaced bowel loops with narrowed lumen causing angulation and kinking of loops with fold tethering
Where is the most common location of a duplication cyst?
Terminal ileum
Biliary gas and mechanical SBO suggests what?
Gallstone ileus
Describe the pathphysiloigy of ascariasis infection
Ingested eggs hatch in the small bowel and penetrate the mucosa
Travel up to lungs by lymphatics/portal system
Travel up bronchi and are swallowed and shed infections eggs
DDx for thin (
Mechanical obstruction
Paralytic Ileus
Scleroderma
Sprue
What are the 5 questions to ask with an SBO?
1 - is there an SBO 2 - where is the obstruction 3 - What is the cause of the obstruction 4 - Are there complications 5 - How should they be treated
Most common cause of mechanical SBO?
Adhesions
What helps to differentiate paralytic ileus vs obstruction
Gas in the colon distal to obstruction
How does scleroderma present in the small bowel?
“hidebound” - dilation and crowding of straight and thin mucosal folds
sacculations of antimesenteric border, occasional pneumotosis cystoides intestinalis (can be due to steroid use)
Differentiate sprue from scleroderma
Sprue will have hypersecretion and normal peristaltic activity
How does sprue present?
Jejunization of the ileum - adaptive response to loss of absorptive surface in proximal small bowel by villous atrophy
Decrease in number of proximal jejunal folds (