Ultrasonography of hepatic mass lesion

This presentation is about radiological features of hepatic benign and malignant mass lesions.

1. ULTRASONOGRAPHY OF HEPATIC MASS LESION DR.ABHILASHA SINGH DNB RESIDENT RADIO-DIAGNOSIS RAMKRISHNA CARE HOSPITAL

2. C haracterization of a known liver lesion (what is it?) D etection (is it there?) F ocused examination

3. Liver mass characterisation B ased on the appearance of the mass on gray- scale imaging and vascular information derived from spectral, color, and power Doppler sonography. G ray-scale : Differentiation of cystic and solid masses, and characteristic appearances Vascular information obtained on conventional Doppler ultra- sound examination. However, Contrast-enhanced CT (CECT) or MRI required for definitive characterization.

4. To address a failed Doppler ultrasound examination of a focal liver lesion, the two basic remedies are : (1) inject a microbubble contrast agent to enhance the Doppler signal from blood (2) use a specialized imaging technique such as pulse inversion sonography, which allows preferential detection of the signal from the contrast agent with suppression of the signal from back- ground tissue. Ultrasound contrast agents currently in use are second-generation agents comprising tiny bubbles of a perfluorocarbon gas contained within a stabilizing shell. Liver lesion characterization with microbubble contrast agents is based on : lesional vascularity lesional enhancement in the arterial and portal venous phase.

5. Lesional vascularity assessment depends on continuous imaging of the agents while they are within the vascular pool. We document the presence, number, distribution, and morphology of any lesional vessels Lesional enhancement is best determined by comparing the echogenicity of the lesion to the echogenicity of the liver at a similar depth on the same frame and requires knowledge of liver blood flow . Vascularity and enhancement patterns of a liver lesion, by comparison, will therefore reflect the actual blood flow and hemodynamics of the lesion in question, such that : A hyperarterialized mass will appear more enhanced against a less enhanced liver o n an arterial phase sequence A hypoperfused lesion will appear as a dark or hypoechoic region within the enhanced liver on an arterial phase sequence.

6. Liver Mass Detection Not size but echogenicity that determines lesion conspicuity on a sonogram. T iny mass of only a few millimeters will be easily seen if it is increased or decreased in echogenicity compared with the adjacent liver parenchyma. E ffective method to date to improve lesion visibility is to perform contrast-enhanced liver ultrasound First technique : 1rst-generation contrast agent Levovist (Schering AG, Berlin). After clearance of the contrast agent from the vascular pool, the micro- bubble persisted in the liver, probably within the Kupffer cells on the basis of phagocytosis . Liver metastases, lacking Kupffer cells, do not enhance and therefore show as black or hypoechoic holes within the enhanced parenchyma.

7. Second technique : CEUS with a perfluorocarbon contrast agent and low-MI scanning in both the arterial and the portal venous phase. Virtually all metastases and HCCs will be unenhanced relative to the liver in the portal phase because the liver parenchyma is optimally enhanced in this phase . H ypervascular liver masses (e.g., HCC, metastases) : will show as hyperechoic masses relative to the liver parenchyma in the arterial phase because they are predominantly supplied by hepatic arterial flow . Enhancement of benign lesions, FNH, and hemangioma generally equals or exceeds liver enhancement in the portal venous phase.

8. Significant lesion , requiring confirmations of their diagnoses : A hypoechoic halo identified around an echogenic or isoechoic liver mass is an ominous sonographic sign necessitating definitive diagnosis. A hypoechoic and solid liver mass is highly likely to be significant and also requires definitive diagnosis. Multiple solid liver masses may be significant and suggest metastatic or multifocal malignant liver disease. However, hemangiomas are also frequently multiple. Clinical history of malignancy, chronic liver disease or hepatitis, and symptoms referable to the liver are requisite information for interpretation of a focal liver lesion.

9. Tumors (I) Benign : 1-Cavernous Hemangioma 2-Focal nodular hyperplasia 3-Adenoma 4-Hemangioendothelioma 5-Mesenchymal Hamartoma 6-Fatty tumors ( II) Malignant : 1-Hepatocellular Carcinoma (HCC) 2-Mets 3-Lymphoma 4-Hepatoblastoma

10. Benign Hepatic Tumors

11. Incidence : -Most common benign tumor of the liver -80% in females , hemangiomas may enlarge particularly during pregnancy or estrogen administration Two types : 1 . Typical Hemangioma : Common Small , asymptomatic D iscovered incidentally 2 . Giant Hemangioma : > 5 cm Uncommon 1 . Cavernous Hemangioma :

12. Ultrasono graphic Features : -Small < 3 cm , well defined , homogenous and hyperechoic -Giant hemangiomas are heterogeneous -Posterior acoustic enhancement is common - E xtremely slow blood flow that will not routinely be detected by either color or duplex Doppler sonography. Histologically : - H emangiomas consist of multiple vascular channels that are lined by a single layer of endothelium and separated and supported by fibrous septa. -The vascular spaces may contain thrombi.

13. When a hyper-echoic lesion typical of a cavernous hemangioma is incidentally discovered, no further examination is usually necessary, or at most, a repeat ultrasound is performed in 3 to 6 months to document lack of change. In a patient with a known malignancy , an increased risk for hepatoma , abnormal results of LFTs, clinical symptoms referable to the liver, or an atypical sonographic pattern, one of the following additional imaging techniques is generally recommended to confirm the suspicion of hemangioma : microbubble- enhanced sonography, CT, red blood cell (RBC) scintigraphy , or MRI.

14. Incidence : - The 2 most common benign liver mass after hemangioma More common in women in childbearing Period ( Hormonal influences may be a factor ) nd 2-Focal Nodular Hyperplasia :

15. Microscopically : Include normal hepatocytes, Kupffer cells, biliary ducts, and the components of portal triads, although no normal portal venous structures are found . As a hyperplastic lesion, there is proliferation of normal, nonneoplastic hepatocytes that are abnormally arranged. Bile ducts and thick-walled arterial vessels are prominent, particularly in the central fibrous scar. The excellent blood supply makes hemorrhage, necrosis, and calcification rare. These lesions often produce a contour abnormality to the surface of the liver or may displace the normal blood vessels within the parenchyma.

16. Ultrasono graphic Features : - Often a subtle liver mass that is difficult to differentiate from in echogenicity from the adjacent liver parenchyma -The central scar may be seen as a hypoechoic linear or stellate area within the central portion of the mass , on occasion may be hyperechoic - Doppler ultrasound highly suggestive, in that well developed peripheral and central blood vessel larger are seen , the blood vessels can be seen to course within the central scar which either a linear or stellate configuration (spoke-wheel vascularity)

17. Incidence : -Less common than FNH -More common in women , increase incidence now due to usage of oral contraceptive agents -Anabolic steroids (typically young men) , Glycogen storage disease -The tumor may be asymptomatic , but often the patient or the physician feels a mass in the right upper quadrant -Pain may occur as a result of bleeding or infarction within the lesion , the most alarming manifestation is shock caused by tumor rupture and hemoprotineum 3-Adenoma

18. Pathologically : a hepatic adenoma is usually solitary, 8 to 15 cm, and well encapsulated. Microscopically : the tumor consists of normal or slightly atypical hepatocytes. Bile ducts and Kupffer cells are few or absent. Hepatic adenomas may show either calcification or fat , both of which appear echogenic on sonography, making their gray-scale appearance suggestive in some cases.

19. Ultrason ographic Features : - Solitary and large at the time of diagnosis (5-15cm) -Non specific , the echogenicity may be hyperechoic ( most common ) , hypoechoic , isoechoic or mixed -With hemorrhage , a fluid component may be evident within or around the mass and free intraperitoneal blood may be seen -A hypoechoic halo of focal fat sparing is also frequently seen -Colour Doppler may show perilesional sinusoid

20. Hepatic adenoma Vs FNH Differentiation of hepatic adenomas from FNH is often not possible by their gray-scale or Doppler characteristics H epatic adenomas are substantially less vascular than most FNH masses and certainly do not show either the intralesional or perilesional vascular tortuosity associated with FNH. Most adenomas are cold on technetium- 99m sulfur colloid imaging as a result of absent or greatly decreased numbers of Kupffer cells. Hepatobiliary scans : These lesions do not contain bile ducts, the tracer is not excreted, and the mass persists as a photon-active region. CEUS; hepatic adenoma is characterized by centripetal filling and non- homogeneity.

21. Incidence : -It is a rare tumor that may occur as a solitary lesion or multifocal nodules ranging in size from few mm upto 15 cm -Most common benign pediatric liver tumor -85% present at < 6 months -Associated cutaneous hemangiomas in 50 % 4-Infantile Hepatic Hemangioendothelioma

22. Son ographic Features : - Appears as a complex, mostly solid hepatic lesion with variable hypo- and hyperechoic echotexture -In cases of significant arteriovenous shunting,dilated hepatic vasculature with prominent blood flow at Doppler US is typical -If large vascular spaces are present, anechoic regions with detectable flow may be seen -The lesions are often well demarcated from the surrounding liver parenchyma

23. Transverse US image shows several small, well-demarcated, homogeneous hypoechoic lesions (arrowheads) in the liver

24. Color Doppler image shows peripheral flow around some of the lesions

25. Incidence : -2 most common benign tumor in pediatric population nd -It typically occurs in children and neonates, with most cases presenting within the first two years of life -Male predominance (2:1) 5-Mesenchymal Hamartoma

26. Son ographic Features : -Mesenchymal hamartomas can show a wide spectrum of radiological features, from being : 1-Predominantly cystic tumor, to 2-Multiseptated cystic tumor, to 3-Mixed solid and cystic tumor, to 4-Even a completely solid tumor -The dominant radiographic pattern, however, is a large (often around 12-15 cm), predominantly cystic mass with internal septations, there can be considerable variation in the size of septae and cystic spaces

27. (a) Transverse US image shows cystic (arrowheads) and solid (T) portions of the tumor and adjacent normal liver ( * ), (b) Longitudinal color Doppler image shows no flow to the cystic component, which contains low-level echoes (arrowhead), minimal flow is seen in the solid component (arrows)

28. Mesenchymal hamartoma in a 2-year-8-month-old boy, A. US shows a large, multiseptated cystic tumor in the right lobe of the liver. The septa of the tumor (arrows) are very thin and regular in thickness, B. CT+C shows a large cystic tumor with fine enhancing septa (arrows) in the liver, there is no solid portion or calcification within the tumor

29. Hepatic lipomas are extremely rare. There is an association between hepatic lipomas and renal angiomyolipomas and tuberous sclerosis. The lesions are asymptomatic. CT confirms the diagnosis and reveals the fatty nature of the mass Angiomyolipomas , by comparison, may also appear echogenic on sonography, although they may have insufficient fat to appear consistently with fatty attenuation on CT, making diagnostic confirmation more difficult without biopsy. 6- Fatty Tumors : Hepatic Lipomas and Angiomyolipoma

30. Malignant Hepatic Neoplasms

31. Incidence : -One of the most common malignant tumors - More in men (M:F - 5:1) - Incidence : Alcoholic cirrhosis Hepatitis B & C Clinical presentation : Often delayed until the tumor reaches an advanced stage . Symptoms include RUQ pain, weight loss, and abdominal swelling when ascites is present. 1-H epatocellular Carcinoma

32. Pathologically, HCC occurs in the following three forms : Solitary tumor Multiple nodules Diffuse infiltration There is a propensity toward venous invasion. The portal vein is involved in 30% to 60% of cases and more often than the hepatic venous system

33. Ultrason ographic Features : - Typically a small focal HCC appears hypoechoic compared to normal liver -Larger lesions are heterogeneous due to fibrosis , fatty change , necrosis and calcification -A peripheral halo of hypoechogenicity may be seen with focal fatty sparing - Small tumors may appear diffusely hyperechoic , secondary to fatty metamorphosis or sinusoidal dilation, making them indistinguishable from focal fatty infiltration , cavernous hemangiomas , and lipomas.

34. Studies evaluating focal liver lesions with duplex Doppler and CDFI suggest HCC has characteristic high-velocity signals Doppler sonography is excellent for detecting neovascularity within tumor thrombi within the portal veins, diagnostic of HCC even without demonstration of the parenchymal lesion CEUS : Lesions are hypervascular , often showing dysmorphic vessels and frequently showing unenhanced regions representing either necrosis or scarring . In the portal venous phase, lesions show washout .

35. Incidence : -Typically these tumors occur in young adults (20 to 40 years of age ) -Unlike HCC they do not have an association with cirrhosis, alcoholism or hepatitis B / C infection, i.e. it occurs in a non-cirrhotic liver Fibrolamellar HCC :

36. U ltrasonographic features : -Fibrolamellar HCCs have nonspecific sonographic features and are seen as well-defined masses of variable echogenicity on ultrasound -Multiphasic CT using a liver protocol or dynamic contrast-enhanced MRI is usually required for further characterization

37. Fibrolamellar hepatocellular carcinoma (HCC) in 23-year-old woman, transverse gray-scale ultrasound image shows large heterogeneous echogenic lesion (curved arrow) in liver, echogenic strands in center of lesion (straight arrow) represent central scar, ultrasound features of fibrolamellar HCC are usually nonspecific

38. Differential Diagnosis : From liver lesions with a central scar 1-FNH 2-Hemangioma (especially if large) 3-HCC (Fibrolamellar type) 4-Cholangiocarcinoma (peripheral type) 5-Hepatic adenoma , metastases (occasionally)

39. Hemangiosarcoma ( Angiosarcoma ) E xtremely rare malignant tumor. A ssociation with specific carcinogens: T horotrast , arsenic , and polyvinyl chloride . Sonographic appearance : Large mass of mixed echogenicity.

40. Hepatic Epithelioid Hemangioendothelioma R are malignant tumor of vascular origin that occurs in adults. Soft tissues, lung, and liver are affected. B egins as multiple hypoechoic nodules, which grow and coalesce over time, forming larger, confluent masses that tend to involve the periphery of the liver. Foci of calcification may be present . The hepatic capsule overlying the lesions of EHE may be retracted inward, secondary to fibrosis incited by the tumor; this unusual feature is highly suggestive of the diagnosis. D iagnosis of hepatic EHE is made by percutaneous liver biopsy and immunohistochemical staining.

41. Incidence : - 18 to 20 times more common than HCC - The most common primary tumor sites : GB , Colon , Stomach , Pancreas , Breast & Lung -Patients with short- term survival (<1 year) after initial detection of liver metastases:HCC and carcinomas of the pancreas, stomach, and esophagus . -Patients with longer- term survival : Head and neck carcinomas and carcinoma of the colon 2-Metastases

42. Ultrason ographic Features : M ultiple solid lesions of varying size and a hypoechoic halo surrounding a liver mass. A halo around the periphery of a liver mass on sonography is an ominous sign strongly associated with malignancy, particularly metastatic disease but also HCC Different appearances : a ) Echogenic metastases b) Hypoechoic c) Target d) Calcified e) Cystic f) Diffuse

43. a) Hyperechoic : -Gastrointestinal origin or from HCC -The more vascular the tumor , the more likely the lesion to be echogenic -Renal cell carcinoma , carcinoid , choriocarcinoma , vascular primaries & islet cell carcinoma - Mimic a hemangioma on sonography

44. b) Hypoechoic : -Hypovascular - U ntreated metastatic breast or lung cancer , as well as gastric, pancreatic, and esophageal tumors -Multiple hypoechoic hepatic masses is more typical of primary NHL of the liver or lymphoma associated with AIDS , however lymphomatous masses may appear anechoic & septated , mimicking hepatic abscesses

45. c) Bull’s eye (target pattern) : -Peripheral hypoechoic zone -The appearance is nonspecific & common , although it is frequently identified in metastases from bronchogenic carcinoma

46. d) Calcified metastases : -Marked echogenicity & distal acoustic shadowing -Mucinous adenocarcinoma , osteosarcoma , chondosarcoma , teratocarcinoma , neuroblastoma -Calcium may appear as large , echogenic & shadowing foci or more often shows innumerable tiny punctate echogenicities without clear shadowing

47. e) Cystic metastases : Ubiquitous benign hepatic cyst, including mural nodules, thick walls, fluid- fluid levels, and internal septations - Necrosis in sarcoma , cystic growth pattern as in cystadenocarcinoma of ovary & pancreas & mucinous carcinoma of colon

48. f) Diffuse (infiltrative) : -Reflects infiltrative metastatic disease and is the most difficult to appreciate on sonography, probably because of the loss of the reference normal liver for comparison - - Breast ,lung carcinomas and malignant melanomas shows this pattern. - The diagnosis can be difficult if the patient has a fatty liver from chemotherapy

49. 3-Lymphoma -Secondary involvement occurs in up to 50 % of patients with systemic lymphoma , but it frequently occult , primary hepatic lymphoma is very rare -Multiple hypoechoic hepatic masses + solid masses at the spleen , kidney , chest … + lymphadenopathy

50. NHL in a 16-year-old girl, (a) US scan shows a large hypoechoic nodule (M) in the right hepatic lobe, K = kidney, L = liver, (b) CT+C shows low-attenuation nodular lesions (arrowheads), a few discrete lesions are evident in both hepatic lobes, with small nodules in the spleen and right kidney

51. Incidence : -Most common primary malignant liver tumor in children -Age : < 2 years Ultras o no graphic Features : -Large hepatic mass -Mixed echogenicity (US), often hyperechoic relative to adjacent liver 4-Hepatoblastoma

52. Transverse US image shows the hyperechoic mass with a lobular margin and hypoechoic septa (arrowheads), arrow = portal vein

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