This article was first published: Digestive Liver Disease Channel of the Medical Community
Author: Du Huayang
This article is reviewed: Yang Health Deputy Chief Physician of the Second People's Hospital of Jingdezhen City
In daily work, we often encounter patients with liver placeholders, and the diagnostic placeholders are often considered step by step according to positioning and characterization, and the final diagnosis is given in combination with the clinical manifestations of patients. However, in the clinic, how to make a clear diagnosis and avoid misdiagnosis when the image is atypical?
The following is to share a case to introduce my diagnostic ideas to my colleagues, hoping to give you some inspiration and help to reduce the occurrence of diagnostic errors.
Review of medical history:
Nausea, vomiting before January without obvious triggers...
Patient, male, 59 years old.
Smoked for about 30 years, with an average of 20 sticks / day, and drank about 30 years, with an average of 1 or 2 liquors per day.
The patient had nausea and vomiting without obvious causes 1 month ago, and denied fever, chills, abdominal pain and other uncomfortable symptoms. He was treated in the local hospital, tested for hepatitis B Xiao Sanyang, and his liver function in our hospital suggested that alanine aminotransferase (ALT) was elevated, and there were no other obvious abnormalities; there were no obvious abnormalities in tumor marker examination.
Liver function tests
Tumor marker examination
Abdominal ultrasound in patients suggests: right lobe of the liver, gallbladder polyps.
To clarify the right lobe of the liver, the patient further enhanced CT, the image is as follows:
Imaging manifestations: round low-density shadow of the right lobe of the liver, patchy fat density shadow seen internally, flat scan CT value of about -12HU, clear boundaries, size of about 8.5 cm×7.5 cm, medium- to severe strengthening of solid components after enhanced scanning, no significant strengthening of fat components, blood supply to the right artery branch of the liver in the mass, poor drainage vein, compression change of the right vein and right branch of the portal vein.
Preliminary considerations: right lobe of the liver occupies a place, malignancy is not excluded, liposarcoma?
CT shows liver mass, how is it diagnosed?
Like our conventional liver placeholder diagnosis idea, the diagnosis of this case is considered from both localization and qualitative aspects, and the localization is liver placeholder, which is very clear. Qualitatively, it is considered from the aspects of benign lesions and malignant lesions. This article will be combined with the literature cases, to give you a brief introduction.
1. Angiomyolioma (AML): mostly occurs in the kidneys, and is rare in the liver. Liver AML border is clear, no envelope, according to the different components, can be divided into lipoma type, fibroid type, hemangioma type.
Lipoma type, containing fat low-density foci, enhanced scanning without strengthening, or strengthened fine blood vessels can be seen in lesions.
Fibroid type, mainly vascular smooth muscle components, almost no fat components, showing progressive strengthening, can bleed, cystic degeneration, necrosis.
Hemangioma type, mainly twisted, coarse vascular component, enhanced scan with aneurysm-like strengthening.
Among them, the presence of fat and blood vessels is an important imaging feature for the diagnosis of AML. Due to the presence of fat components, a flat CT scan reveals the presence of all or part of the tumor's fat density, and mriography shows the reduction of some or all of the signal of the inverted tumor and the presence of lipid peaks in proton spectroscopy imaging.
Fig. A hepatic angiomyolioma, lesion containing more fat (fine arrow), CT value of about -15 ~ -25HU, internal strengthening of twisted vascular shadow through fat (coarse arrow);
Fig. B Multi-angiomyolioma in the liver with multiple angiomyoliomas in both kidneys. In this case, the liver AML is of the lipoma type, and no strengthening and arterial enhancement are seen.
2. Hepatic adenoma: women of childbearing age and oral contraceptive history are the most helpful in diagnosing hepatic adenoma. Hepatic adenoma cells are normal liver cells with glycogen and fat accumulation, which are larger than normal liver cells. Therefore, its fat distribution is uniform, most of the total tumors in the arterial stage of CT/MRI enhancement scan are significantly strengthened, the strengthening of the portal pulse stage is decreased, the delayed period is mainly manifested as isometric density, and there is a low-density ring wrapped around the periphery of the lesion (false envelope), which is prone to bleeding, necrosis, and steatosis in the tumor. MRI manifestations of hepatic adenomas are diverse and lack characteristic manifestations.
Female, 48 years old. Liver mass is found on physical examination. A. Flat CT scan showed that the hepatic left lobe was subcapsular and the density was uneven; B-D. (arterial stage, portal phase, delayed phase, respectively) The arterial phase of the mass was uneven and significantly strengthened, and the degree of strengthening of the mass in the portal and delayed phases was lower than that of normal liver parenchymal strengthening, showing a relatively low density.
3. Hepatic focal nodular hyperplasia: steatosis is rare and usually distributed in patches.
Typical manifestations: larger central scars and separation, centrifugal enhancement wheels, the arterial phase after enhancement is mostly uniform and high density, the central fiber scar is not strengthened in the early stage, the degree of lesion strengthening in the portal phase and delayed phase is reduced, and the central scar is delayed strengthening. MRI flat scanning showed uniform T1 and isoton T2 signals, and the central scar showed a high signal on T2WI, which was characteristic; the enhancement method of enhanced scanning was similar to CT, the arterial phase lesion was significantly strengthened, the central scar was not strengthened, the portal pulse stage and delay period were slightly higher or equal signal, and the central scar was delayed.
A flat scan of the liver shows a circular, slightly less dense foci with a clearer border and a low-density scar foci in the center (Figure A); on enhanced scanning, the lesion strengthens rapidly, the arterial phase shows a significant high density, and the central scar is not significantly strengthened (Figure B); the visible density in the portal phase is still slightly higher than that of the surrounding liver, and the central scar is still low density (Figure C).
At the age of 54, female, the right lobe of the liver has a T2WI high signal, T1 isophasic is equal-low signal, the internal signal of the inverted phase lesion is significantly reduced, the arterial stage is significantly strengthened after enhancement, the central scar of the lesion is low signal, the delayed phase of the lesion is equal signal, and the central scar is significantly strengthened. HE staining may reveal hepatocyte steatosis within the lesion.
4. Teratoma: Primary hepatic teratoma is extremely rare (clinical work, I have not encountered it), mostly abdominal or retroperitoneal teratoma invades the liver, containing fat, liquid and calcification.
There are multiple round mixed density shadows in the right lobe of the liver, and fat shadows and calcification foci can be seen inside
1. Hepatocellular carcinoma fat deposition: tumor necrosis is caused by steatosis, so fat is scattered in distribution, and some literature is called "mosaic" distribution.
Female, 74 years old, hepatitis B, history of cirrhosis, A.MRI scan shows a circular mass shadow in the lower right lobe of the liver, chemical displacement imaging T1Wl in-Phase image shows plaque-like high signal in the mass; B.T1WI out-phase shows a decrease in the tumor part of the signal, showing a low signal, indicating the presence of fat components; C.FS T2WI is slightly higher signal; D.T2WI is uneven high signal; E.FS T1WI is low signal, and the internal flaky high signal is indicated, indicating the presence of bleeding F. MRI dynamically enhances the uneven patchy strengthening of the arterial stage, and the contrast agent withdrawal in the portal phase and the edge extension phase is partially low-signal. Pathology shows hepatocellular carcinoma.
2. Liver metastases: everyone's grasp of liver metastases has been very strong, for example: metastases have a history of primary tumors; strengthen the typical "bull's eye signs". It should be noted that there is no fat in general liver metastases; very few liver metastases have focal fat, and the primary incidence of such fat-containing metastases is mostly fat-containing malignant tumors, such as malignant teratoma liver metastasis. In some cases, liver metastases are found first, followed by primary lesions. Imaging presents with multiple liver lesions, a few may be single, patchy, irregular fat density/signal can be seen in the lesion, and in some cases, bleeding and necrosis may be combined, and the enhanced scan is mostly ring-shaped strengthening.
3. Liposarcoma: it is a rare malignant parenchymal tumor, accounting for about 15% of all sarcomas. Liposarcomas common retroperitoneal metastases, with only 10% of liver metastases. Most liver liposarcomas are metastatic, and single liposarcomas originating in the liver are relatively rare (therefore, do not easily diagnose liposarcoma).
Hepatic liposarcoma CT scan shows uneven low-density mass shadow in the liver, which can be seen more or less of the lower density fat component, the boundary of the mass is not clear, it shows infiltrative growth, and it is unevenly strengthened after strengthening.
Through localization and qualitative diagnosis, it is suspected that the patient is malignant and may be hepatic liposarcoma. Benign lesions are not excluded, and liver AML may be.
Determine the diagnostic idea,
Perfect examination, the cause is unexpected
Therefore, the patient surgically removed the liver lesion in our hospital, the general pathology in the operation: part of the liver tissue was removed, the size was 10.6×10×5.5cm, the surface part was coated, it was still smooth, the area away from the section was 11.5 × 13.5cm, the rest was the membrane, which had been cut open by the clinical part, the page was cut open, the incision surface saw a mass size of 9×8×6.2 cm, the tumor cut face gray powder, gray red, colorful, solid, medium, boundary still clear, adjacent to the cover film and the section. Pathological diagnosis: differentiated hepatocellular carcinoma (right hepatoma), adjacent to the membrane, no special ones are seen from the section.
Pathological diagram
Finally, we can determine that this is lipid-containing hepatocellular carcinoma. Although there is a coarse vascular shadow in the arterial phase, there is no imaging "fast-forward and fast-out" intensification (patchy strengthening of the arterial phase mass margin) of hepatocellular carcinoma (HCC) that we have traditionally seen.
Let's review the relevant content of fatty hepatocellular carcinoma.
Fat-containing HCC (referred to as lipid-containing liver cancer) refers to fat accumulation in cancerous tissue and/or cancer cells with obvious steatosis, fat-containing HCC is a relatively rare special type of HCC, accounting for about 0% to 2% of hepatocellular carcinoma, so it is easier to misdiagnose than typical HCC. Small liver cancers <3 cm in diameter are prone to steatosis, and as the volume of liver cancer grows, steatosis is rare. Patients often have a background of hepatitis and cirrhosis, and biochemical tests have a high serum alpha-fetoprotein (AFP), but they are not specific. (The AFP in this example is not high, and it is easy to miss HCC).
■ The formation mechanism of steatosis within the tumor
Lipid HCC is mainly located in the peripheral area such as the subcapsulation of the liver, and there is significantly more steatosis in the peripheral area than in the central area of fat-containing HCC, which may be related to the relative insufficiency of blood supply. The peripheral area is relatively far from the main trunk of the liver vessels, and the blood supply compensation is relatively inferior to the liver cells in the near main trunk, and HCC is a hyperbolic tumor with rich blood supply and high metabolism, and the energy demand is relatively high, so when HCC occurs in the subcapsular region of the liver, the blood supply is insufficient, and the tumor cells will be at a low or hypoxic level, resulting in steatosis.
■ Lipid HCC imaging performance
Fat-containing HCC is mostly a single nodule, mostly located in the peripheral area of the liver, mainly located in the subcapsular region Lipid HCC has a typical image manifestation of ordinary HCC, that is, "fast-forward and fast-out" strengthening; delayed pseudo-envelope-like strengthening of steatotic cells are mainly scattered in the surrounding area of the lesion in the form of small patches, and the central area is relatively rare adipose tissue. On MRI, T1WI, T2WI high signal, fat inhibition sequence low signal, steatosis decreased in the inverted phase signal.
The biggest difference between HCC is that it contains fat components in tumor tissue, and when HCC is small, it can cause a decrease in the density of lesions and a decrease in the degree of intensification due to steatosis. It may be due to an even distribution of fat. At this time, CT is often not easy to detect, and the signal that is characteristic on the inverted phase image is significantly reduced during magnetic resonance chemical displacement echo sequence examination. When the fat component contained in HCC is large, it can be changed like a lipoma, which is manifested as a uniform or uneven low-density shadow of about -40~-10Hu on CT, and a characteristic change of T1WI high signal, T2WI low signal, and low signal on MRI.
Lessons learned
At this time, we will review the case shared today: at the beginning of the diagnosis, due to the negative AFP, imaging did not have the typical reinforcement method of traditional HCC, and the lesion was relatively limited, so there was not much consideration for HCC. Coupled with the complex imaging components of patients, we first consider malignant liposarcoma, while primary liposarcoma is rare, and the general image lump boundary is not clear, but the imaging boundary in this case is clear. Second, consider benign AML, AML does not have a coating, the patient image has a coating, and the envelope is strengthened. Patients themselves have hepatitis B underlying disease and should give more consideration to common liver cancer.
The final pathological diagnosis is lipid HCC, and the three common characteristic manifestations of lipid HCC are as follows:
(1) Location of lesions: Fat-containing HCC is mostly located at the edge of the liver.
(2) Fat location: Steatosis cells are mainly scattered in the area around the lesion in the form of patches, and the central area is relatively rare.
(3) Strengthening characteristics: with the typical "fast-forward and fast-out" reinforcement form of ordinary HCC, the arterial phase can be seen twisted to strengthen the vascular shadow and irregular reinforcement separation, the delayed period of separation is not obvious, and the marginal envelope of the lesion is gradually strengthened.
Finally, I would like to give you some small warnings, in the diagnosis of imaging, we must follow: common manifestations of common diseases, rare manifestations of common diseases. Common manifestations of rare diseases, rare manifestations of rare diseases.
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