IMAGING IN SMALL BOWEL TUMORS

Dr. Muhammad Bin ZulfiqarPGR-III FCPS SIMS/SHL

Special thanks to RA

Imaging Modalities

USG Barium Meal & Follow Through Conventional Enteroclysis Conventional CT abdomen with I/V

Contrast CT Enteroclysis MR Enteroclysis PET Scan

CT & MR ENTEROCLYSIS IS BEST TECHNIQUE OF MR ENTEROCLYSIS: For MR enterography and

enteroclysis fluid (water or methylcellulose) is the enteric contrast media low signal on T1-weighted images high signal on T2-weighted images

coronal T2W-image

coronal T1W-image with fatsat.

CT ENTEROCLYSIS

Water and Methyl Cellulose is used as Contrast Media

Bowel Luminal Distension > 2cm Bowel Wall Thickness > 3mm always

abnormal for this level of dilatation.

AIMS:

Most common tumors Metastatic depostion Mimics

Most Common

Bowel tumors are relatively rare and accounts for 3-6 % tumors

Adenocarcinoma Lymphoma Carcinoid Gastrointestinal Stromal Tumor

Adenocarcinoma

25-40 of small bowel neoplasm 50 % more common 50 % occur in duodenum, 2nd most

common site is jejunum

Adenocarcinoma

Risk factors: HNPCC - hereditary nonpolyposis

colorectal cancer. Familial adenomatous polyposis. Peutz-Jeghers. Celiac disease. Crohn's disease - occurrence in the

ileum is often related to Crohn's disease.

Typical Features:

focal unilocular circumferential mass with shouldering of the

margins and obstruction. Ulceration is a quite common feature. Extraluminal infiltration can present as fat

stranding. Less frequently adenocarcinoma present as

an intraluminal polypoid mass, which can lead to intussusception.

Stenotic lesion in the duodenum as a result of an adenocarcinoma (yellow arrow).

Not possible to separate from the pancreas (red arrow). Pre-stenotic dilatation of the duodenum.

Coronal MR T2 WI demonstrates irregular wall thickening in the distal duodenum (arrows)--Duodenal carcinoma presenting

Adenocarcinomas often show moderate enhancement, while carcinoid tumors show bright enhancement.

Metastases to the liver and peritoneum occur frequently. CT images show a circumferential mass with shouldering

of the margins.

an irregular mass in the proximal jejunum.Although it is a large circumferential growing mass, the lumen is not obstructed.

There is a large conglomerate of hypodense lymph nodes in the adjacent mesentery, consistent with necrotic lumph node metastases (lower image).

This proved to be an adenocarcinoma, but these findings could very well represent a lymphoma.

Axial and coronal CT images show extensive wall thickening of the proximal jejunum with aneurysmatic dilatation.

On top of our differential diagnostic list would be a lymphoma, but this proved to be an adenocarcinoma.

DD Aenocarcinoma and Lymphoma Features that favor adenocarcinoma

are fat stranding due to mesenteric fat infiltration and lymph node metastases.

In lymphoma fat stranding is uncommon, but lymph node metastases do occur and are usually more bulky.

CT images show a short obstructing circular mass in the jejunum (yellow arrow) with enlarged lymph node (red arrow).This proved to be an adenocarcinoma.

Post-contrast T1W-image with fatsat (left) and T2W-image (right) show an obstructing mass in the jejunum with shouldering (arrow).There is prestenotic dilatation.

Top images show a circular mass in the proximal jejunum with FDG uptake (yellow arrows).

Lower MR-images show the same jejunal mass with shouldered borders consistent with adenocarcinoma.

Obstructing lesion in the ileum with shouldering leading to small bowel obstruction (yellow arrow).

Here an adenocarcinoma in the proximal jejunum.The mass is better depicted with MRI than with CT.

Occurrence in the ileum is often related to Crohn's disease There is a thickened wall of the ileum with adjacent

mesenteric infiltration with foci of extraluminal air indicating perforation.

Crohn's Disease with no Adenocarcinoma Diffuse wall thickening in the distal ileum. Comb sign: hypervascularity in the

adjacent mesentery.

There are multiple lymph nodes (red arrow) and there is fat stranding (yellow arrows).

It should not be mistaken for mesenteric panniculitis as these large necrotic lymph nodes are pathologic.

Lymphoma

Lymphomas make up about 20 % of all small bowel tumors.

The distal ileum is the most common site Risk factors:

Celiac disease Crohn's disease SLE immunocompromised state a history of chemotherapy or extra-intestinal

lymphoma.

Imaging Features:

The typical presentation of a small bowel lymphoma

Thick walled infiltrating mass With Aneurysmal dilatation without obstruction

Bulky mesenteric or retroperitoneal lymphadenopathy and splenomegaly

A less common presentation is as an intraluminal polypoid mass or a large eccentric mass with extension into the surrounding soft tissues with possible ulceration and formation of fistulas.

There is irregular wall thickening of the terminal ileum with aneurysmatic dilatation.

Here a typical lymphoma presenting as a large thick walled mass in the proximal jejunum with FDG uptake.Dilated lumen at the site of the mass and prestenotic dilatation of the duodenum (red arrow)

Reversed fold pattern indicating celiac disease Ileal-ileal intussusception (yellow arrow), in a patient with

multifocal small bowel lymphoma (not all lesions shown here). Mesenteric lymphadenopathy (red arrows).

Enteropathy Associate T cell Lymphoma

There is an irregular mass in the jejunum with luminal dilatation.

There is infiltration of the mesentery. Pathology showed a T-cell lymphoma in celiac disease.

There is an irregular mass in the jejunum

There is infiltration of the mesentery FDG PET shows marked tracer

uptake

Carcinoid Tumors

Carcinoid tumors are rare neuroendocrine tumors.

Well-differentiated - also known as carcinoid

Poorly differentiated - small or large cell neuroendocrine carcinoma.

Carcinoid tumors constitute 2% of all gastrointestinal tumors.

Carcinoid Tumors

The most common location of a carcinoid is the appendix

The second most common location is the distal ileum.

Small bowel carcinoids are multiple in about one third of cases.

There is an association with multiple endocrine neoplasia type I (MEN I).

CT Images Small intraluminal mass in the ileum (yellow arrow). Associated spiculated mesenteric mass with adjacent desmoplastic reaction in small bowel carcinoid.

Here a typical carcinoid presenting as a large mesenteric mass with desmoplastic reaction and retraction of adjacent small bowel loops with wall thickening (arrows).

Carcinoid Metastasis: Related to size of primary tumor > 2 cm High likelihood of metastasis upto

80 % to liver and adjacent lymph nodes.

Same patient. Four years after the initial CT multiple

liver metastases are seen. Shows hypervascular enhancement

pattern in the late arterial phase.

Carcinoid Syndrome:

The carcinoid syndrome occurs in approximately 5% of carcinoid tumors.

commonly occurs in patients who have liver metastases.Symptoms flushing diarrhea and

less frequently bronchospasm and heart failure.

CT Axial & Coronal images show a carcinoid tumor presenting as a hypervascular mass (red arrow) with desmoplastic reaction (yellow arrow).

Carcinoid presenting as hyperenhancing lesion in the late arterial phase

Gastrointestinal Stromal Tumors:

Gastrointestinal stromal tumors are mesenchymal tumors and represent 9% of all small bowel tumors.

most frequently occur in the stomach, followed by jejunum and ileum.

About 20-30 % of GIST's are malignant at presentation. In the small bowel they are more often malignant than

in the stomach. Tumors smaller than 2 cm are usually benign, whereas

masses larger than 5 cm are often malignant. Malignant GIST's predominantly grow extraluminally

and can show necrosis, hemorrhage, calcification (post therapy) and fistula formation.

Gastrointestinal Stromal Tumors:

Features: GIST is a well defined and exophytic mass with

heterogeneous enhancement and a clear delineation from the mesentery.

Unlike carcinoid tumors, the primary lesion in a GIST is large.

Liver metastases are usually hypervascular Despite radical surgical resection, 40-90 % of

patients have recurrence of disease in liver or mesentery.

Typical GIST in the ileum presenting as an exophytic tumor.

CT Axial, Coronal And MR T1 Fat Sat image shows an exophystic mass lesion near duodenojejunal flexure

Disease recurrence in resected GIST showing hypodense liver metastases and a large heterogeneous peritoneal metastasis.

Adenocarcinoma

Lymphoma

Carcinoid GIST

Risk FactorsHNPCCFamilial Adenomatosis polyposisPeutz JeghersCeliac DiseaseCrohn’s Disease

Celiac DiseaseCrohn’s DiseaseSLEImmunodeficiency statesExtra intestinal LymphomaPost radiation

LocationDuodenum>Jejunum>Ilium

Terminal ilium Appendix,Distal Ilium

Stomach>> Small bowel

Key FeaturesFocal circumferential mass with shouldered borders

Thick walled infiltrating mass with aneurysmal dilatation

Transmural hypervascular massThick bowel wallDesmoplastic reactionMesenteric mass

Well defined exophytic mass

EnhancementModerate and Heterogeneous

Homogeneous Hypervascular Heterogeneous

Associated Features

Splenomegaly, Mesenteric and retroperitoneal lymphadenopathy

Carcinoid syndrome< 10%Liver Mets

Hypervascular liver metsNo L/N MetsMesenteric Mets recurrent disease

Diff. DiagnosisLarge Lymphoma Large

Adenocarcinoma

Sclerosing mesenteritis

Lymphoma

Differential Diagnosis

The most common small bowel tumors are metastases

The differential diagnosis of small bowel tumors includes many infectious and inflammatory diseases, that all present with focal bowel wall thickening.

Metastasis

Spread of metastases to the small bowel Intraperitoneal Hematogenous, Lymphatic Direct extension.

Most common (50%) is “Intraperitoneal seeding”. Most Common Sites:

Ovary Appendix Colon

Hematogenous metastases usually occur in breast carcinoma, melanoma and renal cell carcinoma.

Multiple Luminal Metastasis in a patient with melanoma

small bowel metastasis.This patient had a history of colon- and esophaguscarcinoma.

This patient has multiple intraluminal small bowel masses (yellow arrows), which appeared to be metastases from an unknown primary.Also note the intussusception (red arrow) en soft tissue metastasis in the left gluteus muscle (blue arrow).

Crohn’s Disease

Crohn's disease with multiple lesions (arrows).

Active Crohn's disease.Long segment of ileal wall thickening with comb sign and transmural enhancement.

Desmoid Tumors

Desmoid is a most common primary tumor of the mesentery and can mimic a malignant bowel- or mesenteric neoplasm.

Benign locally aggressive mass There is often a history of previous abdominal surgery. Desmoid tumors do not metastasize, but do tend to recur.

Mesenteric desmoids usually show minimal enhancement.FEATURES:

Small bowel or mesenteric vessels can be displaced or encased.Because these tumors can be very hard, percutaneous biopsy can be challenging.

Adenomas

Adenomas are pre-cancerous lesions present as polypoid pedunculated masses on a stalk, a

sessile mass (no stalk) or a mural based nodule within the mucosa.

Lesions show homogeneous enhancement and are usually nonobstructive.

Extraserosal extension is suggestive of malignant degeneration.

MR T2 WI shows multiple small bowel polyps, mainly located in jejunum(patient with Peutz-Jeghers syndrome)

Polyposis Syndrome

Peutz Jagher Syndrome Familial Adenomatous

Polyposis(Gardener Syndrome) Multiple Polyps are seen

Patient with Peutz-Jeghers syndrome with ileal polyp as leadpoint for intussusception.

Others

Hemangioma Leiomyoma Lipoma Mesenteric Ischemia Typhilitis

Referrences

by Rinze Reinhard and Gerdien Kramer Radiology department of the VU medical centre, Amsterdam, the Netherlands Publicationdate May 21, 2014

MRI of the small-bowel: how to differentiate primary neoplasms and mimickers.G. Masselli, M.C. Colaiacomo, G. Marcelli et al.Br J Radiol 2012; 85: 824-837

Thank You