Carcinoma pancreas - USG and CT

60 Year old female with history of pain abdomen and weight loss. USG showing well defined hypoechoic mass lesion in the region of body and tail of the pancreas with mild to moderate vascularity. It also shows few necrotic areas.

Axial CT scan showing well defined heterogeneously enhancing mass lesion arising from the body and tail of the pancreas showing areas of necrosis and causing mass effect on the adjacent structures however no obvious infiltration of the surrounding structures.

USG Guided FNAC showing the lesion with echogenic linier needle (arrow head)

Discussion:

Pancreatic adenocarcinoma is the second most common cause of death from GI cancers. 

Adenocarcinoma ususally arise from pancreatic ducts (99%) and other site being acinar cells (1%).
More than 90% of pancreatic cancers appear in the late stage of disease.

Role of radiology:
1. Early detection.
2. Determination of resectability of the tumor.
3. Relationship to surrounding vasculature.

Multiphasic contrast enhanced study of upper abdomen in Multislice CT scan is the preferred investigation of choice.
CT Scan features include:
1. Alterations in morphology of the gland.
2. Obliteration of peripancreatic fat.
3. Loss of sharp margins with surrounding structures.
4. Involvement of adjacent vessels - is the sign of unresectability.
5. Regional lymph node enlargement.
5. Pancreatic ductal dilatation, pancreatic atrophy, and obstruction of the common bile duct (CBD)

MRI: Role of MRI is yet to be firmly established. T1-weighted fat-suppressed spin-echo and single–breath-hold gradient-echo fast low-angle shot (FLASH) sequences with gadolinium enhancement are valuable for tumor detection.

USG:
The lesion may have a variable appearance on US. It may be hypoechoic, isoechoic, or hyperechoic to the normal pancreas.
Pancreatic ductal dilatation and biliary ductal dilatation are easily demonstrated in patients with a tumor in the head of pancreas that causes an obstruction.
Lymphadenopathy, the relation of the tumor to peripancreatic vessels, and the tumor margins are demonstrated less reliably with US than with other modalities.

Splenic Artery Aneurysm in Extrahepatic Portal Vein Obstruction - CT Angio

Axial thick MIP image of CT angiography showing aneurysm arising from the main splenic artery

Coronal thick MIP image of CT angiography showing aneurysm arising from the main splenic artery

3 D volume rendering image of CT angiography showing aneurysm arising from the main splenic artery (arrow).

Axial CT image in venous phase showing multiple collateral veins in the porta with non visualised main portal vein consistent with extra heaptic portal vein obstruction. Note splenomegaly and multiple leinorenal collaterals.

Discussion:

Splenic artery aneurysms (SAA) are the most common visceral aneurysm occuring predominantly in females. SAA causing EHPVO and presenting with features of portal hypertension is extremely rare.

Women are affected four times more commonly by SAA and often during pregnancy and childbearing years due to endocrine changes.

The usual location of splenic artery aneurysm is at the mid or distal portion of the splenic artery, frequently found at the arterial bifurcation.

Clinical features: They are usually asymptomatic, and the symptomatic presentation includes chronic abdominal pain of varied severity or an acute rupture with hypotension.

Radiology:
CT angiography is the best modality for the diagnosis, although it is usually detected incidentally.

Treatment:
Endovascular: Coiling or covered stent.
Operative: Aneursyectomy with or without splenectomy.

Hemangioendothelioma-CT

3 month old male child came with clinically enlarged nodular palpable liver. CT scan shows enlarged liver with multiple peripherally enhancing variable sized nodular lesion seen occupying whole of the liver in both the lobes. Infra renal part of aorta is small in caliber (arrow head) with dilated and prominant celiac axis (not shown here). There is also similar lesion seen in the upper back subcutaneous region on right side. Features suggestive of hemangioendothelioma.

Discussion:

Benign hemangioendothelioma is a rare liver neoplasm, however it represents the most common vascular tumor of the liver in the neonate. 

The neonatal clinical presentation of hemangioendothelioma includes: 

1) gross liver enlargement, 

2) high-output cardiac failure, and 

3) associated hemangiomas in other organs including skin (hemangiomatosis).

Other complications include consumptive coagulopathy, hemolytic anemia, tumor rupture, and problematic surgical intervention. Hemangioendotheliomas have been recognized on obstetric ultrasound. Neonatal CT, repeat sonography, MRI imaging, and arteriography have all been utilized to visualize the tumor and assess it's size, location, and the anatomy of arterio-venous malformation (AVM) in the neonate. 

The antenatal ultrasound features of hemangioendothelioma include: liver mass (heterogeneous, hypoechoic, complex with anechoic spaces, and hyperechoic), consequent liver enlargement, prominent vasculature, cardiomegaly, and possible hydrops (serous effusions and body edema).Color and pulsed Doppler interrogation can also be particularly useful in identifying an AVM.Post natal findings are liver enlargement, multiple or single confluent liver masses showing peripheral enhancement, may find AV malformation. Typically the celiac axis will be dilated and reduced caliber of infra renal aorta. May find extrahepatic hemangioendothelioma.

Adrenal Myelolipoma - CT

CT scan of a 25 year old female showing well defined fat containing lesions seen in the region of right adrenal gland (arrow) suggestive of adrenal myelolipoma.

Adrenal myelolipoma is an uncommon, benign, endocrinologically inactive tumor of unknown pathogenesis composed of adipose and myeloid tissue. Majority of the lesions are detected incidentally. In most lesions, the fatty component is predominant and is recognizable on radiologic images. Such lesions are radiolucent on radiographs, hyperechoic on sonograms, have low attenuation on CT scans, and have bright signal intensity on T1 -weighted MR images and intermediate signal intensity on T2- weighted MR images.

Tumors composed primarily of myeloid tissue may be hypoechoic on sonograms and will have the imaging characteristics of red marrow on other kinds of images. In complicated cases in which infarction or hematoma is present, the margins of the lesions may be irregular and infiltrative, with blood dissecting through the retroperitoneum. The imaging findings of acute, subacute, or chronic hematoma will then be superimposed on the lesion. When lesions are fatty, well marginated, uncomplicated, and in the position of the adrenal gland, a specific radiologic diagnosis is possible. However, the mere presence of fat in an adrenal mass is insufficient for diagnosis, because a metastasis or other aggressive lesion may engulf fat as it spreads. Nonspecific calcification may sometimes present.