Spectrum of Liver Pathology in Dyskeratosis Congenita

Dyskeratosis congenita (DC) is a rare multisystemic disorder associated with defective telomere maintenance. Frequent clinical manifestations of DC include reticular skin pigmentation, dystrophic nails, oral leukoplakia, and bone marrow failure. Hepatic disturbances are reported to occur in 7% of DC patients. This study aimed to evaluate the histopathologic spectrum of hepatic involvement in this disorder. DC patients with liver tissue in the pathology database at Boston Children's Hospital from 1995 to 2022 were identified. Clinical and pathologic information was documented. Thirteen specimens from 11 DC patients were included (M:F = 7:4; median age at the time of liver tissue evaluation: 18 y). DC-associated gene mutations were identified in 9 patients; TERF1-interacting nuclear factor 2 ( TINF2) was the most frequently represented gene mutation, seen in 4 patients. All patients had bone marrow failure, whereas dystrophic nails, cutaneous abnormal pigmentation, and oral leukoplakia were noted in 73%, 64%, and 55% of patients, respectively. Seven patients underwent bone marrow transplants before biopsy/autopsy (median interval of 45 mo). Histologically, 3 of 4 patients who presented with portal hypertension showed noncirrhotic changes (nodular regenerative hyperplasia and/or obliterative portal venopathy), whereas prominent central and sinusoidal fibrosis was noted in patients with intrahepatic shunting and those showing features of chronic passive congestion. All cases showed hepatocyte anisonucleosis. One patient developed hepatic angiosarcoma, and another 1 had colorectal adenocarcinoma metastatic to the liver. DC patients show heterogeneous histologic findings in their liver. The findings of noncirrhotic portal hypertension, intrahepatic shunting, and angiosarcoma suggest vascular functional/structural pathology as a possible unifying etiology of hepatic manifestations of DC.

Paediatric porto-sinusoidal vascular disease: Two different clinical phenotypes with subtle histological differences

BACKGROUND AND AIMS

In paediatrics, porto-sinusoidal vascular disease (PSVD) is relatively unknown and probably underdiagnosed. We aimed to describe clinical phenotypes, histology and outcome of children diagnosed with PSVD.

METHODS

Retrospective multicentre study of children diagnosed with PSVD. Diagnosis of PSVD was based on histopathology reports; liver specimens were re-evaluated by two expert liver pathologists.

RESULTS

Sixty two children diagnosed with PSVD (M/F = 36/26, median age 6.6 years, range 3.3-10.6), from 7 centres, were included. Thirty-six presented with non-cirrhotic portal hypertension, PH, (PH-PSVD Group = 58%) while 26 had a liver biopsy because of chronic elevation of transaminases without PH (noPH-PSVD Group = 42%). On histology review, the two groups differed for the prevalence of obliterative portal venopathy (more prevalent in PH-PSVD, p = 0.005), and hypervascularised portal tracts (more common in noPH-PSVD, p = 0.039), the other histological changes were equally distributed. At multivariate analysis, platelet count ≤185 000/mm³ was the only independent determinant of PH (p < 0.001). After a median follow-up of 7 years (range 3.0-11.2), in PH-PSVD group 3/36 (8%) required TIPS placement, 5/36 (14%) developed pulmonary vascular complications of PH, and 7/36 (19%) required liver transplantation. In noPH-PSVD none progressed to PH nor had complications.

CONCLUSIONS

Paediatric patients with PSVD present with two different clinical phenotypes, one characterised by PH and one by chronic elevation of transaminases without PH. PSVD should be included among the conditions causing isolated hypertransaminasaemia. On histology, the differences between the two groups are subtle. Medium-term outcome is favourable in patients without PH; progression of the disease is observed in those with PH.

Porto-sinusoidal vascular disorder

It is well established that portal hypertension can occur in the absence of cirrhosis, as reported in patients with immune disorders, infections and thrombophilia. However, similar histological abnormalities primarily affecting the hepatic sinusoidal and (peri)portal vasculature have also been observed in patients without portal hypertension. Thus, the term porto-sinusoidal vascular disorder (PSVD) has recently been introduced to describe a group of vascular diseases of the liver featuring lesions encompassing the portal venules and sinusoids, irrespective of the presence/absence of portal hypertension. Liver biopsy is fundamental for PSVD diagnosis. Specific histology findings include nodular regenerative hyperplasia, obliterative portal venopathy/portal vein stenosis and incomplete septal fibrosis/cirrhosis. Since other conditions including alcohol-related and non-alcoholic fatty liver disease, or viral hepatitis, or the presence of portal vein thrombosis may occur in patients with PSVD, their relative contribution to liver damage should be carefully assessed. In addition to histology and clinical diagnostic criteria, imaging and non-invasive tests such as liver and spleen stiffness measurements could aid in the diagnostic workup. The introduction of PSVD as a novel clinical entity will facilitate collaborative studies and investigations into the underlying molecular pathomechanisms encompassed by this term.

Identification and clinical significance of nodular regenerative hyperplasia in primary sclerosing cholangitis

BACKGROUND AND AIM

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and fibrosis of intrahepatic and extrahepatic bile ducts. PSC is frequently associated with inflammatory bowel disease (IBD). Nodular regenerative hyperplasia (NRH) can occur in IBD with the use or even in the absence of thiopurine treatment. We aimed to study the significance of the presence of NRH and obliterative portal venopathy (OPV), both causes of non-cirrhotic portal hypertension (NCPH), in patients having PSC.

METHODS

Patients with PSC and concurrent NRH on liver biopsy were identified from the digital pathology database covering the period 2003-2019. Evaluation of liver biopsy and the original diagnoses were confirmed on review based on standard histological features diagnostic for NRH and OPV. Clinical and laboratory data were obtained from electronic medical records.

RESULTS

Thirty-one patients (21 male, 10 female; median age at biopsy 40.1 years) were included in the study. Twelve (38.7%) patients had OPV in addition to NRH on the liver biopsy. Nineteen (61.2%) patients had IBD including 11 with Crohn's disease (CD), 7 with ulcerative colitis (UC), and 1 with indeterminate colitis. Thirteen (41.9%) patients had evidence of portal hypertension, 10 (32.2%) with esophageal varices, 4 (12.9%) with history of variceal bleeding, 6 (19.3%) with ascites, and 14 (12.9%) with splenomegaly. Eleven (35.4%) patients had a cirrhotic-appearing liver on imaging. Twelve (38.7%) patients had a history of prior or current thiopurine use.

CONCLUSIONS

The current study suggests that NRH with or without OPV independently occurs in patients having PSC and may lead to NCPH, even in the absence of concurrent IBD and/or thiopurine therapy.

Aberrant von Willebrand factor expression of sinusoidal endothelial cells and quiescence of hepatic stellate cells in nodular regenerative hyperplasia and obliterative portal venopathy

AIMS

Nodular regenerative hyperplasia (NRH) and obliterative portal venopathy (OPV), entities that comprise idiopathic non-cirrhotic portal hypertension (INCPH), are under-recognised diseases of uncertain aetiology and the diagnosis can be easily missed on liver biopsy. The expression of CD34 and von Willebrand factor (vWF) in liver sinusoidal endothelial cells (LSEC) and alpha-smooth muscle actin (ASMA) in hepatic stellate cells (HSCs) is unknown in NRH and OPV. We sought to investigate the pathogenesis and potential immunomarkers that might aid in making the diagnosis of NRH and OPV.

METHODS AND RESULTS

Immunohistochemical (IHC) staining for CD34, vWF and ASMA was performed in clinically and histologically well-characterised NRH (n = 15) and OPV (n = 47) liver specimens. Among the 47 OPV cases, 37 (78.7%) had concurrent features of NRH. CD34 positive staining was mainly confined to small vessels in the portal tracts and LSECs in periportal areas, a finding similar to that in non-NRH/OPV livers. However, expression of vWF in LSECs was positive in the compressed sinusoids of NRH and in a patchy or geographic pattern, particularly prominent in the perivenular areas and dilated sinusoids of OPV cases. HSCs were negative for ASMA in all NRH and OPV cases.

CONCLUSION

Our findings indicate that NRH may be a subtle but common concurrent morphological feature in OPV. The aberrant expression of vWF in LSECs suggests that endothelial injury may play a role in the pathogenesis, which may thus aid in the recognition and diagnosis of NRH and OPV, particularly when confronted with otherwise apparent normal liver histology on needle biopsy.

What makes non-cirrhotic portal hypertension a common disease in India? Analysis for environmental factors

In India, an unexplained enteropathy is present in a majority of non-cirrhotic intrahepatic portal hypertension (NCIPH) patients. Small intestinal bacterial contamination and tropical enteropathy could trigger inflammatory stimuli and activate the endothelium in the portal venous system. Groundwater contaminated with arsenic is an environmental factor of epidemic proportions in large areas of India which has similar consequences. Von Willebrand factor (a sticky protein) expressed by activated endothelium may promote formation of platelet microthrombi and occlusion of intrahepatic portal vein branches leading to NCIPH. Environmental factors linked to suboptimal hygiene and sanitation, which enter through the gastrointestinal (GI) tract, predispose to platelet plugging onto activated endothelium in portal microcirculation. Thus, NCIPH, an example of poverty linked thrombophilia, is a disease mainly affecting the lower socio-economic strata of Indian population. Public health measures to improve sanitation, provide clean drinking water and eliminate arsenic contamination of drinking water are urgently needed. Till such time as these environmental factors are addressed, NCIPH is likely to remain 'an Indian disease'.

Obliterative portal venopathy: A histopathologic finding associated with chronic antibody-mediated rejection in pediatric liver allografts

The significance of post-transplant HLA DSA and chronic AMR in LT is an emerging field of study. Although OPV has previously been described as a histopathologic finding in DSA-positive adult LT recipients, it was not included in the recent Banff criteria for chronic AMR. Our aim was to describe the association between OPV and chronic AMR in pediatric LT recipients. A retrospective review of 67 liver biopsies performed between November 2014 and April 2016 in 45 pediatric LT recipients identified four patients with OPV. Clinical status, liver biochemistry, the presence of DSA, and available non-HLA antibody testing, as well as histopathologic features of chronic AMR, were assessed. All four patients with OPV had class II DSA and histopathologic features of chronic AMR based on the Banff criteria. Two patients were noted to have non-HLA antibodies. Three patients are undergoing treatment with IVIG but have persistent DSA. Two patients have graft failure and are awaiting retransplantation. In conclusion, OPV is a histopathologic finding associated with chronic AMR in pediatric LT recipients. Further studies are needed to elucidate whether OPV is reversible and/or amenable to medical therapy.

Idiopathic noncirrhotic portal hypertension: current perspectives

The term idiopathic noncirrhotic portal hypertension (INCPH) has been recently proposed to replace terms, such as hepatoportal sclerosis, idiopathic portal hypertension, incomplete septal cirrhosis, and nodular regenerative hyperplasia, used to describe patients with a hepatic presinusoidal cause of portal hypertension of unknown etiology, characterized by features of portal hypertension (esophageal varices, nonmalignant ascites, porto-venous collaterals), splenomegaly, patent portal, and hepatic veins and no clinical and histological signs of cirrhosis. Physicians should learn to look for this condition in a number of clinical settings, including cryptogenic cirrhosis, a disease known to be associated with INCPH, drug administration, and even chronic alterations in liver function tests. Once INCPH is clinically suspected, liver histology becomes mandatory for the correct diagnosis. However, pathologists should be familiar with the histological features of INCPH, especially in cases in which histology is not only requested to exclude liver cirrhosis.

Prevalence and clinical significance of nodular regenerative hyperplasia in liver biopsies

BACKGROUND

Nodular regenerative hyperplasia (NRH) is a rare histological disorder associated with a wide variety of systemic diseases.

AIMS

We aimed (i) to report the prevalence of NRH in a database of liver biopsies (LBs) and the frequency of portal hypertension (PHT) at diagnosis, and (ii) to investigate whether associated diseases and/or specific histological lesions, including abnormalities of the microvasculature, were related to PHT.

METHODS

Patients with a histological diagnosis of NRH, referred by seven clinical departments, were retrospectively selected. Clinical, biological, radiological, haemodynamic and endoscopic data at diagnosis were recorded. LBs were reassessed for microvascular abnormalities.

RESULTS

NRH was diagnosed in 4.4% of LBs (n = 159, male: 52%, mean age: 54). Among patients referred for unexplained liver enzyme abnormalities, 15% had NRH. PHT was present at diagnosis in 45 patients (38%), including 13 with portal thrombosis; 65% of patients had an associated disorder. Obliteration of portal vein branches, observed in the LBs of 17 patients (11%), was significantly associated with PHT (P = 0.02). Periportal angiomatosis, observed in 101 patients (63%), was associated with the absence of PHT (P < 10(-4) ).

CONCLUSION

We suggest that NRH is a frequent histological lesion in the setting of unexplained liver enzyme abnormalities. PHT is present at the time of diagnosis in 1/3 of patients regardless of the presence of associated disease. The frequency of periportal angiomatosis in NRH without obliteration of portal vein branches, and its association with the absence of PHT suggest that obstructive portal venopathy would not represent the most frequent mechanism involved in NRH.

Obliterative portal venopathy without portal hypertension: an underestimated condition

BACKGROUND & AIMS

Obliterative portal venopathy without portal hypertension has been described by a single study in a limited number of patients, thus very little is known about this clinical condition. This study aimed to investigate the prevalence of obliterative portal venopathy and its clinical-pathological correlations in patients with cryptogenic chronic liver test abnormalities without clinical signs of portal hypertension.

METHODS

We analysed 482 liver biopsies from adults with non-cirrhotic cryptogenic chronic liver disorders and without any clinical signs of portal hypertension, consecutively enrolled in a 5-year period. Twenty cases of idiopathic non-cirrhotic portal hypertension diagnosed in the same period, were included for comparison. Histological findings were matched with clinical and laboratory features.

RESULTS

Obliterative portal venopathy was identified in 94 (19.5%) of 482 subjects and in all 20 cases of idiopathic non-cirrhotic portal hypertension: both groups shared the entire spectrum of histological changes described in the latter condition. The prevalence of incomplete fibrous septa and nodular regenerative hyperplasia was higher in the biopsies of idiopathic non-cirrhotic portal hypertension (P = 0.006 and P = 0.002), a possible hint of a more advanced stage of the disease. The two groups also shared several clinical laboratory features, including a similar liver function test profile, concomitant prothrombotic conditions and extrahepatic autoimmune disorders.

CONCLUSION

Obliterative portal venopathy occurs in a substantial proportion of patients with unexplained chronic abnormal liver function tests without portal hypertension. The clinical-pathological profile of these subjects suggests that they may be in an early (non-symptomatic) stage of idiopathic non-cirrhotic portal hypertension.

Hepatoportal sclerosis (obliterative portal venopathy) and nodular regenerative hyperplasia in a patient with myasthenia gravis: A case report and review of the published work

Nodular regenerative hyperplasia (NRH) and hepatoportal sclerosis, also known as obliterative portal venopathy (OPV), are two causes of non-cirrhotic portal hypertension (NCPH). NCPH is an increasingly recognized entity that can be seen in association with collagen vascular diseases and with the use of medications such as azathioprine and didanosine, but oftentimes the etiology remains unidentified. We herein report a case of NCPH occurring due to OPV and NRH in a 64-year-old woman with myasthenia gravis (MG), status post-thymectomy. Portal hypertension was diagnosed incidentally on computed tomography in the absence of predisposing factors. Extensive work-up to determine the etiology of any underlying liver disease was unrevealing. NRH and OPV were identified on liver biopsy. Subsequently, the patient had variceal bleeding that necessitated transjugular intrahepatic portosystemic shunt placement. A few similar cases of NCPH occurring in the setting of MG have been previously reported, suggesting that the immunological mechanisms involved in the pathogenesis of myasthenia may also have contributed to the development of NCPH.