Granulomas in the liver

Granulomatous liver diseases

A granuloma is a discrete collection of activated macrophages and other inflammatory cells. Hepatic granulomas can be a manifestation of localized liver disease or be a part of a systemic process, usually infectious or autoimmune. A liver biopsy is required for the detection and evaluation of granulomatous liver diseases. The prevalence of granulomas on liver biopsy varies from 1% to 15%. They may be an incidental finding in an asymptomatic individual, or they may represent granulomatous hepatitis with potential to progress to liver failure, or in chronic disease, to cirrhosis. This review focuses on pathogenesis, histological features of granulomatous liver diseases, and most common etiologies, knowledge that is essential for timely diagnosis and intervention.

Is the carotenoid production from Phaffia rhodozyma yeast genuinely sustainable? a comprehensive analysis of biocompatibility, environmental assessment, and techno-economic constraints

Microorganisms, such as yeasts, filamentous fungi, bacteria, and microalgae, have gained significant attention due to their potential in producing commercially valuable natural carotenoids. In recent years, Phaffia rhodozyma yeasts have emerged as intriguing non-conventional sources of carotenoids, particularly astaxanthin and β-carotene. However, the shift from academic exploration to effective industrial implementation has been challenging to achieve. This study aims to bridge this gap by assessing various scenarios for carotenoid production and recovery. It explores the use of ionic liquids (ILs) and bio-based solvents (ethanol) to ensure safe extraction. The evaluation includes a comprehensive analysis involving Life Cycle Assessment (LCA), biocompatibility assessment, and Techno-Economic Analysis (TEA) of two integrated technologies that utilize choline-based ILs and ethanol (EtOH) for astaxanthin (+β-carotene) recovery from P. rhodozyma cells. This work evaluates the potential sustainability of integrating these alternative solvents within a yeast-based bioeconomy.

A Pattern-Based Approach to Hepatic Infections

The evaluation of liver biopsies for infection can be a challenging and frustrating situation for diagnostic pathologists as well as clinicians. Patients often present with nonspecific symptoms, such as fever and elevated transaminases, leading to a broad differential diagnosis that typically includes malignancy and noninfectious inflammatory diseases in addition to infections. A pattern-based histologic approach can be extremely helpful in both making a diagnosis and guiding the next steps for the evaluation of the pathology specimen as well as the patient. This review discusses several of the more commonly encountered histologic patterns associated with hepatic infectious diseases, the most common pathogens with which they are associated, and helpful ancillary studies.

[Hepatic granuloma-A diagnostic challenge]

Hepatic granulomas can have various causes and their detection requires a systematic diagnostic evaluation. First, identification of risk factors for granulomatous diseases and the exclusion of extrahepatic organ manifestation are necessary. Laboratory investigations and serological screening for the most common underlying diseases of liver granulomas in Germany, such as primary biliary cholangitis (PBC), sarcoidosis and infectious causes (primarily tuberculosis and hepatitis C infections), are recommended. A liver biopsy is essential for confirming the diagnosis, whereby a minilaparoscopically guided tissue sampling offers many advantages, such as the macroscopic detection of granulomas on the liver surface, on the peritoneum or on the spleen. Whether the detection of hepatic granulomas results in a therapeutic consequence, depends decisively on the underlying primary disease. If hepatic granulomas are present without concomitant liver parenchymal damage or other manifestations that would make treatment necessary, a watch and wait approach under close clinical and laboratory monitoring is sufficient. If liver values increase or in cases of hepatic parenchymal damage, urgent treatment of the underlying disease is indicated.

[Drug-induced liver injury-significance of pathology]

Many different medical agents, herbal products, and dietary supplements can induce drug-induced liver injury (DILI) as a clinically relevant complication. DILI, which is direct toxic or idiosyncratic, can have a broad spectrum of clinical appearances from elevation of liver enzymes to acute liver failure. DILI is categorized clinically according to the pattern of serum parameters or pathologically according to the pattern of histomorphology. Histopathological patterns can be described as hepatitic, granulomatous, cholestatic, ductopenic, fibrotic, steatotic, steatohepatitic, and vascular. Correlation to the corresponding drug can be carried out with the corresponding databases (US National Library of Medicine, Liver Tox; www.ncbi.nlm.nih.gov/books/NBK547852/ ). Liver biopsy, in contrast to a clinical/serological diagnostic, has the advantage of an exact resolution with evidence of pathophysiology, activity, regeneration, chronification, and prognosis. Co-occurrence of underlying liver disease can be excluded or confirmed. Histological patterns of DILI are described and illustrated. A diagnostic algorithm for the interpretation of liver biopsies is provided.

Mycobacterium chimaera Hepatitis: A New Disease Entity

Mycobacterium chimaera was identified as a species within the Mycobacterium avium complex in 2004. Until recently, it was predominantly seen in immunocompromised patients. In 2015, an outbreak of disseminated M. chimaera disease was described in European patients after undergoing open-heart surgery in which contaminated heater-cooler water units were used. Using whole genomic sequencing and phylogenetic analysis, investigators found a highly clonal outbreak from the German manufacturing site of the heater-cooler water units. This outbreak has now proven to be world-wide. Patients present with fever, fatigue, and weight loss months to many years after surgery. They are found to have systemic manifestations, including endocarditis, pancytopenia, renal dysfunction, chorioretinitis, and hepatitis. Preliminary reports suggest a high mortality rate despite aggressive treatment. In some patients, the predominant laboratory abnormalities are elevations in liver function tests, leading to diagnostic hepatobiliary work-ups, including liver biopsy. The pathologic changes in the liver have not yet been described. Herein, we report the clinicopathologic findings of the largest series of M. chimaera liver disease in the United States to date: 7 cases within a large, multihospital health care network. Five (71%) patients died of disease, despite aggressive treatment. Liver function test abnormalities were predominantly biliary: mean values of alkaline phosphate 288 U/L, aspartate aminotransferase 79 U/L, alanine aminotransferase 64 U/L. All 7 biopsies showed a consistent and characteristic dual pattern of injury: small, ill-formed collections of sinusoidal histiocytes with rare multinucleated giant cells, and scattered architectural changes of venous outflow obstruction. Two (29%) cases showed mild pericellular fibrosis. Nodular regenerative hyperplasia was seen in 2 (29%) cases, consistent with a sinusoidal/venous obstructive pattern of injury. We postulate that the sinusoidal location of the granulomas contributes to the venous obstructive changes. Recognition of this characteristic dual pattern of injury can allow pathologists to suggest the diagnosis and prompt the appropriate diagnostic and therapeutic interventions.

Multisystemic sarcoidosis-important lessons learnt from one of the great imitators

We report a case of a woman who was admitted with a suspicion of metastatic malignancy of unknown primary origin. A few months prior to her admission, she presented to a rheumatologist with acute anterior uveitis, psoriasiform rashes and polyarthritis. A diagnosis of psoriatic arthropathy was made and she was treated accordingly. Soon after she presented with persistent back and right upper quadrant abdominal pain for which she had a CT scan done with evidence of hilar lymphadenopathy, liver hypodensities and lytic-sclerotic bone lesions. She was referred to our hospital for further investigations and management. After re-exploring her clinical presentation and further investigations (including a liver biopsy), a diagnosis of multisystemic sarcoidosis with ocular, reticuloendothelial, hepatic and skeletal involvement was made. The patient was started on systemic glucocorticoids and second line immunosuppressants and demonstrated significant clinical improvement with resolution of her liver granulomata on imaging and improvement in her back pain. The case illustrates the importance of a thorough clinical assessment, review of investigations and an open mind in the evaluation of a patient.

Granulomas in the Liver, with a Focus on Infectious Causes

Hepatic granulomas are encountered in approximately 2% to 10% of liver biopsies. There are many potential infectious and noninfectious causes; granulomas can be generally classified by their morphology, which may be helpful in refining the differential diagnosis. This article provides a review of hepatic granulomas with an emphasis on infectious causes.

Allopurinol-Induced Granulomatous Hepatitis: A Case Report and Review of Literature

Liver enzyme elevation is a common reason for referral to a gastroenterologist. Drugs are one of the most common reasons for asymptomatic elevation of liver enzymes. We present here a case of granulomatous hepatitis (GH) secondary to long-term use of allopurinol. An 83-year-old male with a history of chronic gout and hypertension was evaluated for elevation of liver enzymes. He denies any complaints of abdominal pain, nausea, fever, chills, weight loss, night sweats, or yellowness of skin. He denies any use of herbal medications. He was on losartan and allopurinol for years. No new medications reported. Physical examination was unremarkable. Labs showed aspartate transaminase 101 U/L, alanine transaminase 81 U/L, and alkaline phosphatase 645 U/L. Ultrasound of the abdomen showed coarse liver texture. Liver biopsy was done that showed mixed GH. Given negative autoimmune and viral serologies, allopurinol-induced GH was suspected. Allopurinol was held, and repeat liver enzymes were checked in 3 months, which showed improvement in transaminase and alkaline phosphatase levels. This case highlights the importance of reviewing medications carefully when evaluating a patient with liver enzymes elevation, as stopping the offending drug can normalize the abnormalities in liver chemistries and can prevent subsequent expensive testing.

Hepatic Granulomas: A Review With Emphasis on Infectious Causes

CONTEXT

Many diseases that cause granulomas or granulomatous inflammation involve the liver. Some of these disease processes are intrinsic hepatic diseases, whereas others are disseminated systemic diseases that involve the liver as well as other organs.

OBJECTIVE

To review the evaluation of granulomas in the liver with an emphasis on infectious causes, as well as the use of special stains, serologic studies, and molecular diagnostic techniques. Pertinent noninfectious causes of hepatic granulomas that are in the differential diagnosis are also discussed.

DATA SOURCES

Literature review and cases acquired during years of practice.

CONCLUSIONS

A wide variety of infectious and noninfectious entities cause hepatic granulomas.

Hepatic crown-like structure: a unique histological feature in non-alcoholic steatohepatitis in mice and humans

Although macrophages are thought to be crucial for the pathogenesis of chronic inflammatory diseases, how they are involved in disease progression from simple steatosis to non-alcoholic steatohepatitis (NASH) is poorly understood. Here we report the unique histological structure termed "hepatic crown-like structures (hCLS)" in the mouse model of human NASH; melanocortin-4 receptor deficient mice fed a Western diet. In hCLS, CD11c-positive macrophages aggregate to surround hepatocytes with large lipid droplets, which is similar to those described in obese adipose tissue. Histological analysis revealed that hCLS is closely associated with activated fibroblasts and collagen deposition. When treatment with clodronate liposomes effectively depletes macrophages scattered in the liver, with those in hCLS intact, hepatic expression of inflammatory and fibrogenic genes is unaffected, suggesting that hCLS is an important source of inflammation and fibrosis during the progression of NASH. Notably, the number of hCLS is positively correlated with the extent of liver fibrosis. We also observed increased number of hCLS in the liver of non-alcoholic fatty liver disease/NASH patients. Collectively, our data provide evidence that hCLS is involved in the development of hepatic inflammation and fibrosis, thereby suggesting its pathophysiologic role in disease progression from simple steatosis to NASH.

Liver immunology

The liver is the largest organ in the body and is generally regarded by nonimmunologists as having little or no lymphoid function. However, such is far from accurate. This review highlights the importance of the liver as a lymphoid organ. Firstly, we discuss experimental data surrounding the role of liver as a lymphoid organ. The liver facilitates tolerance rather than immunoreactivity, which protects the host from antigenic overload of dietary components and drugs derived from the gut and it is instrumental to fetal immune tolerance. Loss of liver tolerance leads to autoaggressive phenomena, which if not controlled by regulatory lymphoid populations, may lead to the induction of autoimmune liver diseases. Liver-related lymphoid subpopulations also act as critical antigen-presenting cells. The study of the immunological properties of liver and delineation of the microenvironment of the intrahepatic milieu in normal and diseased livers provides a platform to understand the hierarchy of a series of detrimental events that lead to immune-mediated destruction of the liver and the rejection of liver allografts. The majority of emphasis within this review will be on the normal mononuclear cell composition of the liver. However, within this context, we will discuss selected, but not all, immune-mediated liver disease and attempt to place these data in the context of human autoimmunity.

Hepatocellular adenomas associated with hepatic granulomas: experience in five cases

We present five cases in whom two rare entities were simultaneously found within the liver, i.e. hepatocellular adenomas (HCAs) and granulomas. Coexistence of both entities confuses diagnosis. Our aim is to disclose the association between HCA and hepatic granulomas. Five patients presented with HCA for which they underwent resection. During laparotomy or at pathological examination, granulomas were found in tumorous and non-tumorous tissue. No specific cause for the granulomas was found. Immunohistochemistry showed overexpression of C-reactive protein and serum amyloid A in 4/5 patients, classifying these lesions as inflammatory HCA. HCA and especially the inflammatory subtype may cause formation of granulomas in (peri-)tumorous tissue as a local response to persistent inflammation and/or the presence of a tumor. Both HCA and hepatic granulomas have also been associated with oral contraceptive use. In conclusion, HCAs associated with hepatic granulomas derive from a local response to (inflammatory) HCA or neoplasm, chronic use of oral contraceptives, or a combination of these factors.

Role for mycobacterial infection in pathogenesis of primary biliary cirrhosis?

Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease characterized by the immune-mediated destruction of biliary epithelial cells in small intrahepatic bile ducts. The disease is characterized by circulating antimitochondrial antibodies (AMAs) as well as disease-specific antinuclear antibodies, cholestatic liver function tests, and characteristic histological features, including granulomas. A variety of organisms are involved in granuloma formation, of which mycobacteria are the most commonly associated. This has led to the hypothesis that mycobacteria may be involved in the pathogenesis of PBC, along with other infectious agents. Additionally, AMAs are found in a subgroup of patients with mycobacterial infections, such as leprosy and pulmonary tuberculosis. Antibodies against species-specific mycobacterial proteins have been reported in patients with PBC, but it is not clear whether these antibodies are specific for the disease. In addition, data in support of the involvement of the role of molecular mimicry between mycobacterial and human mitochondrial antigens as triggers of cross-reactive immune responses leading to the loss of immunological tolerance, and the induction of pathological features have been published. Thus, antibodies against mycobacterial heat shock protein appear to cross-recognize AMA-specific autoantigens, but it is not clear whether these autoantibodies are mycobacterium-species-specific, and whether they are pathogenic or incidental. The view that mycobacteria are infectious triggers of PBC is intriguing, but the data provided so far are not conclusive.

Hepatic granulomas: a clinicopathologic analysis of 86 cases

The aim of this study was to determine the prevalence and histopathological characteristics of hepatic granulomas. All records of liver biopsies/resections evaluated in our pathology department between 2002 and 2009 were retrospectively reviewed. Specimens with hepatic granulomas were reexamined by a designated pathologist. Type and localization of granulomas, size of granulomas and epithelioid histiocytes, and the morphological findings of surrounding liver tissue were recorded in an attempt to establish a correlation with relevant clinical, laboratory and radiological findings. Out of 1420 liver biopsy/resected specimens evaluated at our institution during the study period, 86 cases of epithelioid cell granulomas (6.05%) were observed. Of the 86 cases, 23 were men and 63 were women. The most common underlying etiology was PBC in 38 patients, infections in 34, malignancies in five, sarcoidosis in four, and foreign bodies in three patients. One case (1.2%) of a drug-induced hepatic granuloma was encountered, while another case was deemed idiopathic (of unknown etiology). Contrary to common belief, granulomas were observed not only in early stage PBC but also in cases with stage 3 disease. Out of all the PBC cases with granulomas, 55.6% had stage 3 disease, and besides periductal granulomas, intraacinar granulomas were also seen. For sarcoidosis, intra- and peri-granulomatous fibrosis was observed in as many as 75% of cases. A large majority of granulomas (82.4%) associated with infections were of the necrotizing type. Extensive evaluation of the morphological characteristics of hepatic granulomas and surrounding liver tissue along with clinical, radiological, and other laboratory findings may help arrive at an accurate diagnosis in a majority of cases. Rather than being a final diagnosis, the presence of hepatic granulomas entails the need for further investigations towards identifying the underlying etiology, with a pathologist being at the center of the diagnostic process.

[Hepatic granulomas]

Liver granulomas are histopathologically defined and associated with various liver and non-livers disorders. There are five main causes of liver granulomatosis: primary biliary cirrhosis, tuberculosis, sarcoidosis, B and C viral hepatitis, and drug related. In the other cases, not associated with an underlying systemic granulomatous disease, a systematic diagnostic approach should be used to identify less common etiologies. After a careful diagnostic work-up, a long-term follow-up of patients with undetermined liver granulomatosis is mandatory as it may be a presenting feature of liver lymphoma.

Granulomatous liver disease

Hepatic granulomas are often encountered on liver biopsy and may represent a primary hepatic process, a manifestation of a systemic illness, or an innocent finding of no clinical relevance. Hepatic granulomas are a unique inflammatory response that may be idiopathic or may be a response to a bacterial, fungal, viral, or parasitic infection; a manifestation of drug-induced liver injury; or a manifestation of underlying malignancy. When granulomas are found on liver biopsy, clinicians must correlate the histologic findings with historical and clinical data to help provide an accurate diagnosis and guide management. Therapy may be warranted, either directly for the granulomatous inflammation of the liver or for a systemic process. For some patients, observation may be the most appropriate form of management.

Hepatic granulomas, with an emphasis on infectious causes

Granulomas are aggregates of macrophages, often admixed with other inflammatory cells, which usually result from chronic antigen presentation. Many diseases that produce granulomas involve the liver. Some are intrinsic hepatic diseases, whereas others are disseminated systemic diseases that involve the liver and other organs. Hepatic granulomas are reportedly present in 2% to 10% of all liver biopsy specimens examined in general practice, and of those supposedly as many as 36% have no discoverable etiology even after extensive evaluation of the specimen. This review focuses on the diagnosis of granulomas in infectious diseases affecting the liver, including use of special stains, serologic studies, and molecular diagnostic techniques, and discusses pertinent noninfectious causes of hepatic granulomas that are in the differential diagnosis.

Hepatic granulomas: histological and molecular pathological approach to differential diagnosis--a study of 442 cases

BACKGROUND/AIMS

The incidence of hepatic granulomas is reported in 2-15% of liver biopsies. This study was carried out to evaluate the incidence and aetiology of hepatic granulomas in a German Institute of Pathology with specialization in liver diseases.

METHODS

A retrospective case review was performed on 12,161 liver biopsies of the Institute of Pathology (University of Cologne) between 1996 and 2004. Aetiology was determined according to histomorphological changes, clinicopathological data and liver tissue polymerase chain reaction (PCR) for detection of diverse putative pathogens in the liver tissue.

RESULTS

Four hundred and forty-two liver biopsies revealed granulomatous lesions (3.63%). Two hundred and fifteen cases (1.77% of all biopsies and 48.64% of granulomatous lesions) were diagnosed as primary biliary cirrhosis. In 37 cases (0.3% of all biopsies and 8.37% of granulomatous lesions), the diagnosis of sarcoidosis was established. A positive PCR result for an infectious pathogen was obtained in 15 samples (3.39%) [Bartonella henselae (n=2), Listeria (n=3), Mycobacterium tuberculosis (n=3), Yersinia pseudotuberculosis (n=1), cytomegalovirus (n=2), Epstein-Barr virus (n=4)]. In six cases, a putative diagnosis was established according to the report of clinical conditions. In 11 cases (2.48%), drugs were the putative causative agent. In 158 cases (36%) a definite diagnosis could not be established.

CONCLUSIONS

Hepatic granulomas have a broad range of underlying aetiologies. With a combined histological, clinical, serological, and molecular approach, we were able to clarify the cause in 64% of the cases. Owing to the diverse prognosis and therapeutic implications, a detailed interdisciplinary workup of all liver biopsies with granulomatous lesions is mandatory.

Cutaneous sarcoidosis and primary biliary cirrhosis: A chance association or related diseases?

Sarcoidosis and primary biliary cirrhosis (PBC) are thought to be two distinct disorders of unknown origin. However, both are characterized by hepatic granuloma formation and may also manifest cutaneous granulomatous inflammation. In this report, we describe two cases of cutaneous sarcoidosis occurring in the setting of PBC and review 7 additional cases from the literature of granulomatous skin disease associated with PBC. Although the pathogenesis of both sarcoidosis and PBC remains elusive, the simultaneous occurrence of these uncommon diseases suggests a common pathway may contribute to granuloma formation in both disorders.