Liver Inflammatory myofibroblastic tumor (IMT) – What's it and what's not
Hello, let’s look at the case first.
On CT performed in a 44 year old woman for weight loss and weakness
liver mass was found, biopsy was performed
which showed low grade sarcoma findings.
In contrast-enhanced CT, a mass with well-defined borders is seen,
with outer hyperemic area and thick hypoenhancing zone,
internal hypervascular area,
And in the center
It shows a geographic hypoenhancing area.
It is similar in the coronal image,
The low shading inside is like the lunar surface
It also looks like the face of an animation character.
On noncontrast MRI T1 and T2 images
No cystic change or necrosis is seen.
In the ADC map, diffusion restriction is remarkable outside and
A less pronounced inner part is distinguished.
In Dynamic MRI
In the arterial stage, there is a wide hyperemic area around the lesion,
There is a thick hypoenhancing zone inside,
The inner side shows strong contrast enhancement at an early stage,
The central part is later enhanced with contrast,
In the equilibrium phase, it shows a higher signal than the surroundings.
Surgically inflammatory myofibroblastic tumor,
IMT has been diagnosed,
They showed positive ALK expression, which is a feature for the diagnosis of IMT.
In this presentation, IMT-like lesions in the liver will be reviewed.
Lesions such as pathologically diagnosed as IMT, but clinically atypical;
those, either IMT or not, diagnosed as an inflammatory pseudotumor,
those that were difficult to distinguish from IMT in biopsy,
and a one diagnosed as IgG-4 related pseudotumor.
IMT consists of fibroblast or myofibroblast,
accompanied by inflammatory infiltrates
It is a tumor with intermediate biological potential.
With no pleomorphism,
plump spindle cells
In loose small bundles,
It is accompanied by infiltration of lymphocytes and plasma cells.
Positive expression for SMA and ALK or ROS1
can an indicator of diagnosis,
May show IgG4 .
Those in which ALK expression is not displayed
are reported to show more aggressive behavior.
As a malignant subtype
epithelioid inflammatory myofibroblastic sarcoma has been reported.
IgG4-related pseudotumor is characterized by
IgG4 ratio of 40% or more,
igG4 cell count 10 or higher.
shows ALK (-)/IgG4(-).
Liver mass found during health chekup for 57 y.o. man.
On the outer area of the mass tha showing clear and smooth boundaries
expanded tumor vessels are visible,
The mass showed a pattern of gradually increasing contrast enhancement.
Unlike the first case we saw earlier
The hypoenhancing zone is not visible,
The internal hypoattenuation is
Coronal reformation shows the same pattern.
Hemorrhage spots are visible in T1WI,
There is a heterogeneous appearance in the T2 and ADC images.
Unlike the first case
There is no distinction between inner and outer areas.
Dynamic MRI is also similar to CT
The tumor vessels are enlarged at the edge of the mass,
Inside, irregular contrast enhancement seems to gradually fill up.
The possibility of HCC showing telangiectatic change,
adenoma and angiosarcoma was suspected.
The pathologic diagnosis suggested IMT, but
In immunostaining findings
SMA, ALK, or ROS1 that are helpful to diagnose IMT
were not expressed.
Unlike the first representative IMT case, the gross appearance is also
There are dilated blood vessels and hemorrhage.
Recurrent tumor was found on CT at 2 years of surgery.
Coronal imaging shows more extensive recurrent tumors.
Only partial resection was performed,
The pathologic findings were similar to those of previously resected lesions, but
Immunostaining findings were not typical of IMT
and are atypical for IMT.
Clinical and imaging findings are also
Unlike typical ALK IMT,
For IMT of ALK and ROS1 negative
I think more research is needed.
On CT of a patient who visited the hospital with fever and chills,
hypoattenuation at the border and center
is visible in a targetoid lesion.
The appearance of several layers
is similar to the first IMT case.
In T2 and ADC images,
targetoid pattern is again seen, but the center shows
a fluid signal suggesting necrotic change
which makes different from the IMT seen earlier.
In Dynamic MRI, the hypoenhancing band and
Having an inner hypervascular area is similar to IMT, but
presence of a part in the center, likely a cystic necrosis,
is not enhanced during the delayed phase, which seems a different finding from IMT.
On imaging, the possibility of subacute abscess,
tuberculoma, and adenocarcinoma was suspected.
As a result of ultrasound-guided biopsy
inflammatory myofibroblastic tumor was reported.
However, after 3 months, it can be seen that the lesion disappeared on CT.
Rather than IMT, it is thought that the inflammatory mass, that is, the abscess, regressed.
Clinically or pathology diagnosis
Let's look at the case of an inflammatory pseudotumor.
In the past, IPT seems to have been commonly used in several different meaning.
First, it was used as a synonym for inflammatory myofibroblastic tumor.
In the current WHO classification
This is described as not recommendable.
Second, it was used as a term referring to tumor-like abscess,
Third, although pathology diagnosis is abscess,
still called IPT because clinically tumor had been suspected.
MRI performed by a 62-year-old man with fever and myalgia.
T1 and T2 images show relatively homogeneous mass.
The upper portion of the mass is
globally enhanced strongly in the arterial phase
then gradually fade out,
In the arterial and portal stage
hypointense rim observed.
At the lower part of the mass
The center is quickly enhanced and then washed out.
The outer side is slowly enhanced with contrast.
On ultrasound examination, the mass shows a relatively homogeneous echo,
Outer hypoechoic rim is clearly visible.
HCC was suspected and TACE was attempted,
in which only mild staining is visible.
Lipiodol is deposited on other parts of the mass.
On CT after one month, Lipiodol was deposited in other areas,
The lesion is as in the previous case
The center area that quickly enhances contrast and
Late contrast enhancing periphery
are observed in an unusual shape
On CT 3 months after TACE
The mass appears slightly larger.
It is similar to IMT, the first case we saw, but
In this case, the center was enhanced early,
and the outer side was enhanced later
It is a reversed pattern.
In surgery, the diagnosis of pathology came out as Inflammatory pseudotumor,
Since this was a case a long time ago, it seems that the distinction from IMT was not clear.
It is believed that IPT was used to refer to IMT.
On CT performed in an 86-year-old man for right upper abdomen pain
HCC was suspected.
With central necrosis of no enhancement
the mass shows a peripheral hyperenhancing area.
Noncontrast MRI in T2WI
The central necrosis area shows a fluid signal.
In Dynamic MRI, the periphery of the mass
Contrast enhancement similar to the liver,
The center is not enhanced with contrast.
What is different from the first IMT case
The central necrosis site shows a fluid signal
It looks like an abscess pocket.
Diagnosis on biopsy results as an inflammatory pseudotumor.
After 4 months, the lesions almost disappeared.
Diagnosis of Inflammatory pseudotumor in he pathology report
is thought to have been used to refer to tumor-like abscess.
On CT performed by a 64 year old woman for abdominal pain
Liver lesions were found.
There was no fever or chills.
Targetoid appearacence in CT and MRI,
It shows delayed enhancement.
Image findings include organizing abscess,
In addition, the inflammatory pseudotumor was identified in an ambiguous meaning.
It shows a target-like appearance even in T1WI,
Relatively homogeneous at T2
Diffusion restriction is not significant
Pathology diagnosis was reported as abscess.
In that Abscess mimics tumor,
Clinically referred to as an inflammatory pseudotumor,
but is different from IMT or IgG4-related pseudotumor.
Liver lesions found on CT of patients with suspected GB cancer
Lesions showing targetoid enhancement was observed.
In MRI, rim enhancement was less pronounced than in CT.
Nonspecific findings in T2 and DWI
cholangiocarcinoma, sclerosing hemangioma,
were differentiated for inflammatory pseudotumor.
There is a polypoid lesion in GB,
Doesn't look like cancer
GB lesion was diagnosed as tubular adenoma.
Liver lesio was diagnosed as IgG4-related hepatopathy, inflammatory pseudotumor.
A mass found in a 52-year-old man,
There is little contrast enhancement except for the border,
It shows different imaging findings from IMT.
In biopsy, schwannoma, angiomyolipoma,
and a possibility of IMT was reported.
In surgery, it was finally diagnosed as schwannoma.
As the imaging findings are different from IMT or angiomyolipoma,
referring to the image findings
could be helpful for differential diagnosis before surgery.
Microscopic findings show that a mass consisting of spindle cells
S-100 protein staining is positive.
Mass found in a man prone to heavy drinking,
Contrast enhancement is weak and late,
Multiple calcifications are visible inside
Dynamic MRI shows rim hyperenhancement at the rim,
Inside, the contrast enhancement is weak,
In Noncontrast MRI
Strong hyperintensity at T2.
colloid type of cholangiocarcinoma or
mucinous metastasis was suspected.
In the Preliminary Report of Pathology
It was a benign spindle cell tumor,
After various immunostaining
Finally diagnosed as schwannoma.
Imaging findings are also different from IMT.
Liver mass found in health checkup.
Irregularly shaped mass
shows APHE and washout.
APHE and washout are also shown in Dynamic MRI,
without capsule or mosaic appearance, etc.
orother ancillary feature.
There was no HCC-risk.
In Noncontrst MRI
homogeneous T2 hyperintensity with
Shows diffusion restriction.
Suspected nonspecific malignant tumor.
Biopsy suspected a variety of possibilities, including IMT.
Through various immunostaining after surgery
Diagnosed as inflammatory angiomyolipoma.
The imaging findings were nonspecific, but
at least different from IMT
IMT is a recent pathologic feature
genetic abnormalities are being elucidated in detail.
However, while ALK/ROS1 negative
some lesions reported as IMT
For those tumors whose imaging and clinical findings differ from IMT,
It is thought that more research is needed to see if there are different types of tumors.in such cases.
Non-IgG4-related peudotumor are also need to be differenitaed,
and differential diagnostic criteria are also being established.
Among imaging findings
presence of an internal geographic area showing differential enhancement
with outer hyperemia
and the peripheral hypoenhancing band
are thought to be a characteristic finding,
the absence of cystic necrosis in the center
is thought to be the difference from abscess.
Imaging tests may guide histologic diagnosis
for difficult cases.