Imaging manifestations of hepatic pseudotumor

Hepatitis pseudotumor

 Inflammatory pseudotumor (IPT) is a tumor-like lesion that can occur in many organs throughout the body
.

  IPT is a well-defined focal lesion formed by fibrous connective tissue hyperplasia with a large number of chronic inflammatory cell infiltration, and it is named because it resembles a tumor mass in gross pathological observation
.

Etiology and pathology:

Four organizational types:  

Clinical features:

Prognosis:

IPL has a good prognosis
.
Some lesions can subside naturally
.
However, due to the current difficulty in distinguishing from hepatic malignancies, surgical resection should be the best option
.
 

CT appearance:

Inflammatory pseudotumor of the liver

CT appearance:

1.
Gradual enhancement from the periphery to the center: Pathological examination showed that the lesion was rich in vascular tissue, infiltrated by a large number of inflammatory cells, and the surrounding tissue was obviously hyperemia, hemorrhage and inflammatory edema, reflecting that the lesion was in the early stage of inflammation
.

2.
There is no obvious enhancement in the lesion: the pathological examination shows that the vascular tissue in the lesion is sparse, mainly coagulation necrosis of different degrees, accompanied by a small amount of lymphocyte infiltration, which reflects that the lesion is in the stage of inflammation and necrosis
.

3.
Peripheral enhancement: The enhancement is manifested as obvious irregular annular enhancement around the periphery, and the enhancement of the delayed scan gradually subsides
.
The pathological examination found that there were few blood vessels in the center of the lesion, mainly infiltration of plasma cells and lymphocytes and coagulation necrosis, and the periphery was mainly fibrous tissue and a large number of capillaries, indicating that the lesion was in the late stage of inflammation
.

in conclusion:

1.
Inflammatory pseudotumor of the liver is mostly manifested as low-density lesions under the capsule, which is not enhanced in the early stage, but can have different forms of enhancement in the portal and delayed stages;

2.
The enhancement mode of lesions is related to different pathological basis and reflects the progress of lesions
.

MR appearance

Differential diagnosis

1.
Hepatocellular carcinoma:

CT examination is mainly characterized by early enhancement
.
The third phase showed the sign of "fast in and fast out"
.
Most of them have a history of hepatitis and liver cirrhosis, and most of them are positive for AFP.
It is not difficult to identify the two
.
However, it is difficult to differentiate from atypical HCC cases, and the final result is based on pathological examination
.

2.
Metastatic liver cancer:

CT and MRI showed typical "target sign" and peritumoral edema
.
After the enhancement, the surrounding ring is strengthened
.
Most had a history of primary tumor
.
The lesions are often multiple, ranging in size, with smooth or not smooth edges, and some have liquefaction necrosis, cystic degeneration and hemorrhage
.

3.
Cholangiocarcinoma:

CT showed a low-density mass with ill-defined borders, uneven and persistent enhancement after enhancement, dilation of bile ducts around the tumor, atrophy of liver lobes, and AFP was mostly negative
.
The identification of the two also has certain difficulties, because the reinforcement methods have certain commonalities
.
 

4.
Liver abscess: CT manifestations are single or multiple low-density areas in the liver parenchyma, which are round or oval with partitions and clear or unclear boundaries
.
Gas-liquid levels were seen in 20% of the lesions
.

The "ring sign" can appear in 90% of the acute phase after enhancement
.
The "tri-ring sign" can be seen in the chronic phase
.
On MRI, the abscess showed long T1 and long T2 signal changes.
The abscess wall showed ring enhancement after GD-DTPA enhancement, but the abscess cavity was not enhanced
.

5.
Hepatocellular adenomas: CT scans are mostly low-density masses with clear borders in the liver, and a few are iso-density masses, and the density increases when complicated with hemorrhage
.
There was fatty degeneration around a part of the tumor, and there were annular low-density shadows surrounding the tumor, which was a characteristic CT manifestation of hepatocellular adenoma
.
In the arterial phase after enhancement, thick blood vessels can be seen running through the tumor
.
MRI showed long T1 and long T2 signal, and STRI showed ring-shaped low signal around the tumor
.
 

Postoperative pathology: hepatic pseudotumor

CT findings: The patient's liver on plain scan showed low-density lesions, nodules and capsule-like enhancement were seen in the arterial phase enhancement, and the capsule enhancement seemed to decrease in the portal venous phase
.
Delay still see envelope enhancement
.

(Hepatitic pseudotumor) Plain scan showed a low density shadow with an irregular outline of the lesion, with unclear and slightly blurred edges
.
The shape seems to be flake or 8-shaped, not obvious spherical
.
There seems to be a separation inside
.
Arterial phase: No obvious enhancement was seen, but the margins and septa appeared to be slightly enhanced
.
Portal phase: moderate enhancement of margins and septa
.
The marginal wall and septum of the lesions were the same density as liver tissue in delayed scan
.

Hepatitic pseudotumor: a slightly hypodense shadow in the right lobe of the liver, with unclear peripheral borders, and a first-class hypodense nodule in the center
.
In the arterial phase, the central nodules have mild enhancement, and necrotic areas can be seen inside.
In the portal venous phase, the lesions gradually enhance outward, and are basically isodensity in the delayed phase
.

Hepatitic pseudotumor: a nodule shadow in the S6 segment of the liver with uniform density, clear boundary and smooth edge, obvious enhancement in the portal venous phase on enhanced scan, the enhancement degree is greater than that of the liver parenchyma, and the enhancement degree of the nodule on delayed scan is less than that of the liver parenchyma
.

Summarize:

The incidence of inflammatory pseudotumor of the liver is low, but the lesions are diverse, and it is easy to be confused with hepatocellular carcinoma and metastatic liver cancer
.