Liver involvement in tuberous sclerosis

Prevalence of Liver Steatosis in Tuberous Sclerosis Complex Patients: A Retrospective Cross-Sectional Study

Introduction: Tuberous sclerosis complex (TSC) is a genetic disease caused by pathogenetic variants in either the TSC1 or TSC2 genes. Consequently, the mechanistic target of the rapamycin complex 1 (mTORC1) pathway, a regulator of cell growth, metabolism, and survival, becomes inappropriately activated, leading to the development of benign tumors in multiple organs. The role of mTORC1 in lipid metabolism and liver steatosis in TSC patients has not been well-studied, and clinical data on liver involvement in this population are scarce. Methods: We conducted a retrospective, cross-sectional study to compare liver steatosis in TSC patients with age-, sex-, BMI-, and diabetes status-matched controls. Participants with a definite diagnosis of TSC were recruited from the TSC clinic at UZ Brussel. Liver steatosis was quantified using the fat signal fraction from in-phase and out-of-phase MRI, with a threshold of ≥5% defining the presence of steatosis. We also evaluated the prevalence of liver angiomyolipomata in the TSC group and analyzed risk factors for both liver steatosis and angiomyolipomata. Results: The study included 59 TSC patients and 59 matched controls. The mean fat signal fraction was 4.0% in the TSC group and 3.9% in the controls, showing no significant difference (two-tailed Wilcoxon signed ranks test, p = 0.950). Liver steatosis was observed in 15.3% of TSC patients compared to 23.7% of the controls, which was not statistically significant (two-tailed McNemar test, p = 0.267). Liver angiomyolipomata were identified in 13.6% of the TSC cohort. Conclusions: Our study, describing in detail the liver phenotype of TSC patients, did not reveal a significant difference in the prevalence of MRI-assessed liver steatosis in a large cohort of TSC patients compared to a closely matched control group.

Concurrent hepatic and renal angiomyolipomas in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a rare disease which is characterized by widespread of a variety of benign tumors in multiple organs. Renal angiomyolipomas (AMLs) are the primary cause of morbidity in TSC due to anemia, renal failure or spontaneous bleeding. In contrast, the hepatic involvement is unusual and it is infrequently described in literature.

Hepatic perivascular epithelioid cell tumours in children with tuberous sclerosis

Perivascular epithelioid cell tumours are a novel histological description of mesenchymal tumours consisting of perivascular and epithelioid cells. Angiomyolipomas are one of the commoner types of this tumour group. They are typically associated with the inherited condition tuberous sclerosis (TS). In TS they are often seen arising in the kidneys and brain, although much more rarely can be seen in the liver. While usually thought of as benign tumours there is little evidence to predict whether they will progress to malignancy. Currently, there is no recommended best management strategy between resection and surveillance. We report two patients with TS seen in our centre with these described PEComa liver lesions histologically, however only one required a resection. On review of the literature, features such as increased size, rapid growth and vascular invasion would be concerning for possible malignant potential and therefore merit resection, as well as significant symptoms.

Liver Angiomyolipomas in Tuberous Sclerosis Complex-Their Incidence and Course

BACKGROUND

The purpose of this study was to evaluate the epidemiology and clinical significance of hepatic angiomyolipomas in patients with tuberous sclerosis complex.

METHODS

We performed a retrospective analysis of clinical and imaging data from 187 patients with tuberous sclerosis complex. The prevalence, progression, and potential relationship between liver lesions and other clinical findings, including genetic associations, were assessed.

RESULTS

Twenty-eight of 187 patients (14.9%) had hepatic lesions. There was a predominance of female over male patients in individuals with liver lesions (17 versus 11), with statistical significance in patients under five years of age (P < 0.05). All individuals having hepatic lesions who also had available genetic testing data (n = 20) were diagnosed with a TSC2 gene mutation. All patients with liver lesions had coexisting renal angiomyolipomas (AMLs) (P < 0.05). The age of onset of renal lesions was lower and their prevalence was significantly higher in patients with liver involvement (P < 0.05). In most instances, hepatic lesions measured several millimeters in diameter and were clinically asymptomatic. Progressive lesion growth was documented in six individuals but with no clinical consequences to date.

CONCLUSIONS

This study confirms the association of hepatic lesions with TSC2 mutations, a common origin of liver and renal AMLs, as well as the predominance of female patients in this group. Hepatic AMLs are relatively common but mostly benign lesions.