Eosinophilic pseudotumor of the liver: report of six cases and review of literature

Imaging Phenotypes and Evolution of Hepatic Langerhans Cell Histiocytosis on CT/MRI: A Retrospective Study of Clinical Cases and Literature Review

(1) Background: pathological changes in hepatic Langerhans cell histiocytosis (LCH) have been observed; however, corresponding imaging findings can appear vague to physicians and radiologists. The present study aimed to comprehensively illustrate the imaging findings of hepatic LCH and to investigate the evolution of LCH-associated lesions. (2) Methods: LCH patients with liver involvement treated at our institution were retrospectively reviewed along with prior studies in PubMed. Initial and follow-up computed tomography (CT) and magnetic resonance imaging (MRI) were systematically reviewed, and three imaging phenotypes were created based on the lesion distribution pattern. Clinical features and prognoses were compared among the three phenotypes. Liver fibrosis was evaluated visually on T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) values of the fibrotic areas were measured. Descriptive statistics and a comparative analysis were used to analyze the data. (3) Results: based on the lesion distribution pattern on CT/MRI scans, patients with liver involvement were categorized as the disseminated lesion phenotype, scattered lesion phenotype, and central periportal lesion phenotype. Patients with scattered lesion phenotype were typically adults, and only a few of them had hepatomegaly (n_present = 1, 1/6, 16.7%) and liver biochemical abnormalities (n_present = 2, 2/6, 33.3%); patients with central periportal lesion phenotype were typically young children, and hepatomegaly and biochemical abnormalities were more apparent in these patients than those with another phenotype; and those with the disseminated lesion phenotype were found in all age groups, and the lesions evolved rapidly on medical imaging. Follow-up MRI scans show more details and can better document the evolution of lesions than CT. T2-hypointense fibrotic changes, including the periportal halo sign (n_present = 2, 2/9, 22.2%), patchy liver parenchyma changes (n_present = 6, 6/9, 66.7%), and giant hepatic nodules close to the central portal vein (n_present = 1, 1/9, 11.1%), were found, while fibrotic changes were not observed in patients with the scattered lesion phenotype. The mean ADC value for the area of liver fibrosis in each patient was lower than the optimal cutoff for significant fibrosis (METAVIR Fibrosis Stage ≥ 2) in a previous study that assessed liver fibrosis in chronic viral hepatitis. (4) Conclusions: The infiltrative lesions and liver fibrosis of hepatic LCH can be well characterized on MRI scans with DWI. The evolution of these lesions was well demonstrated on follow-up MRI scans.

Hepatic Langerhans Cell Histiocytosis (LCH) Presenting as a Harbinger of Multisystem LCH

Langerhans cell histiocytosis (LCH) is a rare systemic disorder characterized by an infiltration of CD1a+/langerin+ histiocytes, commonly involving bone, skin, and lymph nodes in children. Hepatic involvement is rarely observed in multisystem LCH. We describe an exceptional case of hepatic LCH in an adult preceding the diagnosis of multisystem LCH, mimicking anti-mitochondrial antibody (AMA)-negative primary biliary cholangitis (PBC). A 65-year-old man presented with intermittent pruritus, weakness, dyspnea, fever, and chills that have been progressive for four years. Physical examination was unremarkable. Laboratory work revealed cholestatic biochemistry profile. Liver biopsy showed portal non-necrotizing granuloma encasing a damaged duct (florid duct lesion), and multifocal lobular Kupffer cell clusters, suggestive of PBC. Tests for autoimmune diseases including AMA were negative. Endoscopic retrograde cholangiopancreatography (ERCP) was negative for biliary obstruction. One month after the liver biopsy, he developed flaky, red, and burning rash on the right scalp, forehead, and epigastric skin. A skin biopsy at an outside institution revealed LCH. Subsequent re-examination of the liver biopsy showed that the histiocytes within the florid duct lesion were positive for CD1a and S-100. Concurrently, a small focus of LCH was noted in his gastric biopsy performed for gastritis symptoms. Hepatic LCH may mimic AMA-negative PBC histologically and clinically and may present as a harbinger of multisystem LCH. While rendering the diagnosis would be challenging without prior history of LCH and with focal involvement, awareness of such presentation and communication with clinical colleagues may be helpful.