Finding clump of cells in liver in AAV is ‘rare but genuine,’ per new study
Manifestation seen in 5 cases tough to diagnose, varies widely
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The presence of clumps of inflammatory cells, or granulomas, in the liver is a rare manifestation of ANCA-associated vasculitis (AAV) that varies widely and can be difficult to diagnose, according to the findings of a new study from Tunisia.
While liver problems are common in AAV, the researchers noted that they don’t usually include these small, localized clusters of immune cells in the organ, known as hepatic granulomatosis. As such, scientists had not established whether or not this symptom could be truly linked to AAV.
In this review, the authors analyzed five published case reports to illustrate the diagnostic challenges and variety of presentations of liver granulomas in AAV.
“Hepatic granulomatosis is a rare but genuine manifestation of ANCA-associated vasculitis,” the team concluded, adding that, in each case, “no confirmed confounding [factors] were identified.”
The researchers noted that, when cases are found, “immunosuppression is the therapeutic cornerstone, with generally favourable outcomes.”
The study, “Hepatic granulomas as a manifestation of ANCA-associated vasculitis:a systematic review,” was published in the journal Frontiers in Immunology.
AAV comprises a group of autoimmune diseases that affect small blood vessels throughout the body. There are three main types of AAV: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The presence of granulomas is a hallmark feature of GPA and EGPA.
Symptoms of AAV depend on where in the body this damage occurs, as the disease can affect several organs.
Little is known about cell clumps involving the liver
About half of people with AAV experience some form of liver (hepatic) involvement. This usually involves biochemical abnormalities but only rarely includes granulomas visible on histological, or microscopic, analysis of liver tissue. “This biochemical hepatic involvement is broadly distinct from true histological hepatic granulomatosis,” the researchers wrote.
Because of the rarity of histological hepatic granulomatosis, there is little scientific understanding of how the condition presents or how to identify it. To address these questions, a team of researchers at the University of Tunis El Manar performed a comprehensive review of published literature on the subject.
In total, the team found five case studies that met their definition of hepatic granulomatosis. Published between 1999 and 2026, these reports — two from the U.S. and one each from Greece, Japan, and Tunisia — described four individuals with GPA and one with EGPA. The patients had a mean age of 57.6 when they started experiencing liver problems.
The scarcity of publications emphasizes how rare hepatic granulomatosis is in AAV, according to the team.
“This rarity stands in contrast to the relatively common biochemical hepatic involvement in AAV,” the researchers wrote, noting this other type is seen in about half of patients during active disease stages.
Across the studies, the microscopic features of the liver abnormalities varied broadly. Biopsies, or the collection of tissue samples for histological analysis, showed granulomas with or without dead tissue at their center. One patient had definitive granulomas in the lungs, but not in the liver, suggesting that liver blood vessel inflammation, rather than direct granuloma formation, was the cause of their liver involvement.
Such differences could make identification of hepatic granulomatosis challenging, the researchers noted. Additionally, two of the cases involved individuals with both AAV and Sjögren’s disease, another rare autoimmune condition, further complicating diagnosis.
Two cases highlighted specific diagnostic challenges, emphasizing that clinicians should consider testing for hepatic granulomatosis in a variety of situations. Taking samples of liver tissue isn’t standard practice in AAV.
However, it could be appropriate and facilitate earlier diagnosis if there are other signs of liver problems beyond biochemical abnormalities, such as abnormal imaging findings, according to the researchers.
One case involved a 51-year-old American woman with GPA whose imaging results raised concerns about liver and pancreatic cancer. A liver biopsy ultimately revealed that the masses were granulomas rather than tumors. This “illustrates the diagnostic pitfall of anchoring on the most feared diagnosis,” the researchers wrote.
Another case was that of a 47-year-old Tunisian woman who had not yet developed any distinctive AAV symptoms. For this patient, the discovery of liver abnormalities came during an unrelated surgery for a hernia. While the woman’s medical team initially suspected sarcoidosis, another autoimmune condition that can cause granuloma formation, blood testing revealed she had AAV and Sjögren’s.
A year later, she began to experience asthma flare-ups and ear, nose, and throat symptoms, which are all common features of EGPA. According to the team, the woman’s liver problems may have gone unrecognized, and her EGPA diagnosis may have been delayed, were it not for the incidental discovery of liver granulomas.
Researchers urge creation of database for unusual cases
Across the reports, several patients responded well to corticosteroids or immunosuppressants, common AAV treatments, the team noted.
“The response to corticosteroids and immunosuppression in the documented cases aligns with broader AAV management principles,” the researchers wrote.
Because one case was ultimately fatal, the team emphasized that potential liver involvement should be taken seriously and treated appropriately.
“Hepatic granulomatosis, given its potential for progressive fibrosis [scarring] … should arguably be classified as organ-threatening and managed accordingly,” the team wrote.
Among the study’s limitations, according to the researchers, was that their search involved only published reports with confirmed diagnoses. “Unreported or misclassified cases of AAV-associated hepatic granulomas almost certainly exist,” the team wrote.
To help facilitate further research, the scientists suggested creating a registry for cases with unusual organ manifestations of AAV, including hepatic granulomatosis. This could help better identify the features of the condition and establish protocols for accurate diagnosis, the team noted.
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