Focal Liver Pathology PDF

Liver Pathology Focal Liver Disease Chapter 9 Edited 1/11/25 1 Before we dive into focal liver disease, let’s remember diffuse liver diseases! 2  Wait…Let’s Ponder? We learned about some diffuse liver diseases last week. What do you think i...

Liver Pathology Focal Liver Disease Chapter 9 Edited 1/11/25 1 Before we dive into focal liver disease, let’s remember diffuse liver diseases! 2  Wait…Let’s Ponder? We learned about some diffuse liver diseases last week. What do you think is the difference between Diffuse Liver Disease and Focal Liver Disease? 3  Hepatic Lesions Contents Hepatic Cysts Parasitic Liver Infestations Hepatic Abscess Benign Focal Liver Lesions Metastatic Liver Tumors Ultrasound Guided Liver Biopsy Liver Trauma 4  Types of Hepatic Lesions Very few hepatic lesions have specific appearances. Therefore, it is important to know the clinical history and laboratory data. A focal hepatic lesion can be any of the below mentioned types. 1. Cyst 2. Abscess 3. Hematoma 4. Primary tumor 5. Metastatic disease 6. Infectious process A CT scan showing a patient with polycystic liver disease, in 7. Infarction or necrosis axial and coronal views 5  Ask Yourself… Is the mass extrahepatic or intrahepatic? Is the local architecture spared or distorted? Is there an invasion of the adjacent structures? Is there a displacement of other landmarks? 6  Descriptive Ultrasound Terminology: Borders: (Familiarize yourself with these terms!) Well defined Distinct Internal Echotexture fluid-filled: Poorly defined Organ-specific location: Anechoic Subtle Right, left, caudate Low-level internal echoes Smooth Subdiaphragmic Fluid level Irregular Periportal Septated Lobulated Pericholecystic Polypoid projections Thickened Subcapsular Thin Internal Echotexture solid: Halo Lesion shape: Homogeneous Round Hypoechoic Count and number: Irregular Heterogeneous Single/solitary Lobulated Coarse echotexture Two/double/duplication Polypoid Patchy echotexture Approximately Wedge-shaped Bulle’s eye/target lesion Multiple Invading Complex Cluster Stellate Calcified Enumerable 7 Cysts 8  Benign Liver Cysts Congenital (due to abnormal development of the biliary radicle) or Acquired (from previous trauma or infection). They are often asymptomatic and incidental findings on ultrasound. Sonographic findings: Single or multiple Simple or complex Anechoic or with debris Well-defined, smooth borders Posterior enhancement Thin capsule Large cysts can compress and displace liver structures. 9  Simple Cyst Sonographic Appearance: Anechoic Well-defined, smooth borders Posterior enhancement Thin capsule 10  Complex Cyst Sonographic Findings: Thin or thick capsule Internal echoes Septations (require careful investigation) Polypoid internal nodules (require careful investigation) Larger cysts may be considered for percutaneous aspiration or decompression. 11 Simple vs. Complex 12  Complex Cysts Predominantly cystic with polypoid Thin-walled, low-level internal echoes - projections hemorrhagic cysts. 13  Polycystic Liver Disease Rare, inherited condition About 60% coincide with polycystic renal disease Progressive formation of multiple cysts from 2 - 3 cm or larger Cysts distributed throughout the parenchyma Larger cysts can obstruct the biliary tree Histologically, polycystic lesions are similar to simple cysts LFTs are within normal limits Resected polycystic liver and transplanting specimen ready for transplant procedure. 14 What is the difference? 15  Let’s Review What is a congenital cyst? How would you describe a simple cyst in ultrasound terms? What makes a cyst complex? What does the prefix “poly” mean? A patient is diagnosed with polycystic liver disease, 60% of these patients will also have what? 16 Parasitic Liver Infestations 17  Echinococcal Cyst: Tapeworm Infestation Infectious disease common in sheep-herding areas and seldom seen in the United States. 1. Liver, brain, and lungs may be the destination organs. 2. Worm resides in dogs' intestines (the adult worm is 3-6mm). 3. The ova from dogs’ feces is ingested by humans. 4. Infected human is an intermediate host 5. In the proximal GI tract of humans, the larvae burrow through the mucosa and enter the portal circulation. 6. Larvae travel to the liver via portal flow. 18 Complications and Treatment The cysts may enlarge and rupture an organ. The cysts may also impinge on the blood vessels and lead to vascular thrombosis and infarction. Anaphylactic shock If left untreated, it may be fatal. Treatment options: Medications – antiparasitic meds Aspiration, injection, re-aspiration Surgical resection 19 Stages of the Disease 20 Echinococcal Cyst Tapeworm Infestation Cyst with daughter cysts within mass 21  Schistosomiasis Schistosomiasis is one of the most common types of parasitic infections in humans. Infection occurs when larval forms of the parasite, released by snails, enter the skin. These worms live in freshwater bodies such as canals, rivers, lakes, ponds, and reservoirs. 22  Schistosomiasis SCHISTOSOMIASIS IS A MAJOR CAUSE OF PORTAL HYPERTENSION WORLDWIDE! Eggs reach the liver through the portal vein, causing a granulomatous reaction, resulting in periportal fibrosis, which then occludes the portal veins and causes portal hypertension. 4 things to remember about Schistosomias: Occluded intrahepatic portal veins Portal hypertension Thickened Portal vein walls Appearance varies based on the stage and species of Schistosoma involved. 23  Schistosomiasis: 2 Types 1. Schistosoma Mansoni: irregular hepatic surface, “mosaic pattern” with echogenic septa outlining polygonal areas of relatively normal liver parenchyma, septal fibrosis, and splenomegaly. 24  2nd Type 2. Schistosoma Japonicum: common features include septal and capsular calcifications, “turtle back sign” which is considered pathognomonic. This sign refers to calcified septa and fibrosis resembling a turtle. 25 Sonographic findings related to AIDS (Acquired Immunodeficiency Syndrome): Pneumocystic Carinii Jiroveci 26  Pneumocystic Carinii Jiroveci Most common opportunistic infection in people with HIV infection This organism is usually responsible for Pneumocystis Pneumonia (a fungal pneumonia). Sonographic findings include hyperechoic, non-shadowing foci throughout the liver. Bile ducts (cholangitis) and gallbladder wall (cholecystitis) are thickened. 27  Pneumocystic Carinii Jiroveci Cholangitis Hyperechoic, non- Cholecystitis shadowing foci 28  More Review Which parasitic infection is a major cause of portal hypertension worldwide? The finding of hyperechoic, non-shadowing foci throughout the liver is seen in what infection? 29 Hepatic Abscess 30  Hepatic Abscess Occur most often as complications of biliary tract disease, GI tract infestation/infection, surgery, or trauma. 3 basic types of abscess formation: 1. intrahepatic 2. subhepatic 3. subphrenic May be solitary or multifocal (50-70% of occurrences) Most common site of solitary occurs in the right lobe of the liver (rt liver is larger part with more blood supply=routes of spread). 31  Please understand that an abscess can occur anywhere in the body. When we say hepatic, we are referring to something within or related to the liver. Hepato means liver. Understand that a “hepatic abscess” is simply an abscess that happens to be in the liver. 32  Pyogenic Abscess: Infectious Condition The most common organisms that cause the bacterial infections are the Escherichia coli (E-coli) and Anaerobes (found in the GI tract and thriving in necrotic tissue, pus) A pyogenic abscess is a pus-forming abscess. Clinical presentation: fever, elevated LFT’s, leukocytosis, pain, pleuritis, nausea, vomiting, diarrhea, anemia 33  Pyogenic Abscess Etiology Bacteria can gain access to the liver via: the biliary tree the portal vein the hepatic artery direct extension from a contiguous infection hepatic trauma Sources of infection include: cholangitis portal pyemia secondary to appendicitis, diverticulitis, inflammatory disease, or colitis direct spread from another organ trauma with direct contamination infarction after embolization or from sickle cell 34  Pyogenic Abscess Appearance Ultrasound appearance may be variable and dependent on the internal content of the mass. Varies in size - 1cm to very large Round or ovoid in shape Acoustic enhancement Complex with debris Debris to fluid level or gas to debris level Internal gas is seen with posterior reverberation artifact, “dirty shadowing,” and as a tiny bright echogenic foci (plural for “focus”). (anaerobes produce CO2, methane, and other gases) What artifact would this create? 35  Pyogenic abscess complex mass with debris and gas Pyogenic Abscess Appearance Hypoechoic abscess masses and Complex collection of pus with gas in biliary system CT scan showing gas to debris gas level 36  Amebic Abscess: Infectious Condition Collection of pus formed by disintegrated tissue in a cavity, usually in the liver, caused by the protozoan parasite Entamoeba histolytica. Infestation happens with the ingestion of an egg, and initially, the parasite colonizes the colon. Infection then spreads via the portal bloodstream. Patients may be asymptomatic or may show gastrointestinal symptoms of abdominal pain, diarrhea, leukocytosis, hepatomegaly, and low fever. The large parasitic colonies may rupture through the diaphragm into the pleural space. 37 Amebic Abscess Travel Plan 38  Amebic Abscess Sonographic appearance: round or oval, not well- defined margins, isoechoic or hypoechoic, posterior enhancement, rupturing into pleural space 39  What is the difference between pyogenic and amebic abscesses? The main differences between the 2 are the causes, symptoms, and treatments. Pyogenic abscesses are caused by bacteria, while amebic abscesses are caused by a protozoan parasite. Pyogenic: Caused by diseases of the biliary tract, infectious gastrointestinal disorders, trauma, or direct extension from an intraabdominal infection Amebic: Caused by the protozoan parasite Entamoeba histolytica, which is acquired by ingesting food or water contaminated by human feces Pyogenic abscesses are more likely to cause jaundice, while amebic abscesses are more likely to cause abdominal pain, fever, and chills. Pyogenic abscesses are treated with antibiotics and drainage, while amebic abscesses are treated with chemotherapy and rarely require drainage. 40  What do these little guys look like? Pyogenic abscess bacteria: Amebic Abscess parasite: Escherichia coli Entamoeba histolytica 41  Hepatic Candidiasis: Infectious Disease Candidiasis is a fungal infection. Most prone to develop candidiasis are immunocompromised people (oncology patients, geriatric population, post-transplant surgery patients, HIV affected). Candida can invade the bloodstream and any organ after that. Axial contrast-enhanced CT image shows multiple Represents clinically with fever, localized pain, hypoattenuating hepatic leukocytosis micro-abscesses. 42  Hepatic Candidiasis Sonographic Appearance: Uniformly hypoechoic masses Sometimes, multiple hypoechoic lesions with echogenic central portion (bull’s eye, wheel- within-wheel, or target appearance) Darker “halo” represents reactive liver tissue. As scar formation develops, pattern becomes echogenic. A biopsy is needed to confirm the diagnosis. Imaging spectrum of the evolution of candidiasis. 43  Do you remember? Where do most solitary hepatic abscesses occur? Why? What does the prefix “pyo” mean? What type of infection is candidiasis? 44  Neoplasms: Benign vs. Malignant 45  Hepatic Tumors Neoplasm – “new, abnormal growth”: can be benign or malignant Benign - occurs locally but does not spread or invade surrounding structures, may push surrounding structures aside or adhere to them, encapsulated masses Liver benign neoplasms – hemangioma, focal nodular hyperplasia, adenoma Malignant - can grow / spread uncontrollably through the bloodstream and lymph nodes, direct invasion of nearby or distant structures, imaging can sometimes differentiate between the two by recognizing the localized invasion Liver malignant neoplasms – hepatoma (HCC), metastatic disease, lymphoma 46 47 Benign Focal Liver Lesions 48  Chronic Granulomatous Disease A granuloma is a mass that forms due to chronic inflammation caused by poorly degradable or unknown antigens. It consists of a group of macrophages that are enclosed in a capsule. This condition can impact multiple organs, including the liver, spleen, lymph nodes, cutaneous tissue, and bones. 49  Chronic Granulomatous Disease Sonographic Appearance: Poorly marginated, hypoechoic mass with posterior enhancement. Chronic granulomas appear as calcifications with posterior shadowing. Granulomas often mimic other pathological lesions. As a result, biopsy is necessary to classify the mass as a granulomatous disease specifically. 50  Cavernous Hemangioma Most common benign neoplasm of the liver Most frequently seen in females Sponge-like tumor, filled with blood Larger hemangiomas can bleed Slow-growing tumor that can undergo degeneration, fibrosis, and calcification Seen in subcapsular liver space and mostly in the right lobe 51  Cavernous Hemangioma Sonographic appearance: Majority are hyperechoic and homogenous Round or slightly lobulated Sharp, well-defined borders Atypical hemangioma changes appearance due to fibrosis, thrombosis, or necrosis. The differential diagnosis for hemangioma should include metastases, hepatoma, focal fatty infiltration, and adenoma. 52 Hemangioma adjacent to portal vein (cine loop) 53  Focal Nodular Hyperplasia (FNH) Second most common benign tumor. Comprises normal Kupfer cells, hepatocytes, and biliary structures. Tissue lacks portal veins and central veins. Formation possibly related to congenital vascular anomaly. Prevalent in females. Asymptomatic condition when mass is smaller. 54 What is hyperplasia? Enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferation. 55 Focal Nodular Hyperplasia FNH is a well-circumscribed, isoechoic lesion. Some are pedunculated. Can grow up to 5 cm. May have a central stellate scar formed by bile ducts and prominent thick-walled arterial vessels. Mass may compress adjacent liver parenchyma and blood vessels. 56  Liver Cell Adenoma Rare, consists of atypical hepatocytes. Mostly seen in females taking contraceptives and people taking steroids. Multiple adenomas seen in people with Glycogen Storage Disorder Type 1 (Von Gierke’s). Can grow up to 15 cm. Liver specimen with Larger tumors can rupture and bleed (manifested with RUQ pain and low hematocrit). adenoma hanging off the left liver lobe. Adenoma has a malignant potential. 57 Liver Cell Adenoma 58  Lipoma and Angiomyolipoma Hepatic lipomas are extremely rare. The association between hepatic lipoma, renal angiomyolipoma, and tuberous sclerosis is recognized. The lesions are asymptomatic. Ultrasound demonstrates a well- defined, echogenic mass indistinguishable from a hemangioma, echogenic metastasis, or focal fat. 59  Let’s think about it! Which benign focal liver lesion is the most common? Which is the second most common? 60 Malignant Liver Tumors 61 Primary Liver Malignancy 62  Hepatocellular Carcinoma Primary malignant tumors are relatively rare in the liver. The most common malignant tumor is hepatocellular carcinoma (HCC), sometimes referred to as hepatoma. Strongly associated with chronic hepatocellular disease (cirrhosis, Hep B and C). Occurs more frequently in men with male to female ratio of 5:1. Increased LFTs and AFP (alpha-fetoprotein-produced by the fetal liver and yolk sac, germ cell tumors, and HCC). 63  Hepatocellular Carcinoma Early-stage is associated with a palpable mass, jaundice, weight loss, and hepatomegaly. Late-stage is associated with portal hypertension, ascites, splenomegaly, and Budd-Chiari syndrome. May present in one of three patterns: solitary massive tumor, multiple nodules throughout the liver, or diffuse infiltrative masses in the liver. There is a tendency toward venous invasion. The portal vein is involved in 30% - 60% of cases and more often than the hepatic venous system. Hepatocellular carcinoma cannot be differentiated from metastases on ultrasound. 64  Multiple solid masses Solitary solid mass Diffused carcinoma throughout 65  HCC mimicking hemangioma The sonographic appearance of the echotexture of HCC is variable. HCC may be hypoechoic, HCC growing in cirrhotic liver complex, or echogenic. Most small (