Sonic hedgehog hepatocellular adenoma: magnetic resonance imaging features and correlation with histology

OBJECTIVES

Sonic hedgehog hepatocellular adenoma (shHCA) is a new hepatocellular adenoma (HCA) subgroup characterized by high risk of hemorrhage. ShHCA account for below 10% of all HCA cases and are often associated with female gender, obesity, and non-alcoholic steatohepatitis. No specific MRI characteristics have been described to date. The objective of this study was to assess the value of using MRI to identify shHCA, and correlate MRI findings with histology.

METHODS

We retrospectively collected MRI scans of 29 patients with shHCA from our center and from different liver referral centers to include 35 lesions. Diagnosis of shHCA was assessed by immunohistochemical overexpression of argininosuccinate synthase 1 or prostaglandin D2 synthase, then confirmed by molecular analysis of sonic hedgehog pathway activation and/or by proteomic analysis.

RESULTS

In 46% (n = 16/35) of shHCA cases, we detected intralesional fluid-filled cavities defined on MR images as fluid-like foci markedly hyperintense on T2-weighted sequences, and hypointense on T1-weighted sequences, with or without delayed enhancement. Pathologically, these cavities were observed in 54% of cases as vacuoles filled with blood at different stages of degradation. Hemorrhage and/or necrosis were detected among 71% of cases by MRI analysis (n = 25/35) versus 82% pathologically. Seventeen percent of shHCA cases (n = 6/35) were completely homogeneous via MRI and pathological analysis. No MRI criteria was found in favor of focal nodular hyperplasia, HNF1A-mutated HCA, or typical inflammatory HCA.

CONCLUSION

We reveal the presence of intralesional fluid-filled cavities among 46% of our shHCA cases that represent a new MRI finding possibly helpful for shHCA diagnosis.

CLINICAL RELEVANCE STATEMENT

This multicenter study is the first clinical study about the radiological aspect of this new hepatocellular adenoma subgroup. This highlights a strong correlation between MRI and histological analysis, with a specific pattern emerging for diagnosis.

KEY POINTS

• Sonic hedgehog hepatocellular adenoma is a new hepatocellular adenoma subgroup associated with high risk of hemorrhage, but imaging features of this subgroup remain unknown. • Analysis of MR images and correlation with pathology revealed intralesional fluid-filled cavities and necrotic-hemorrhagic changes. • Intralesional fluid-filled cavities have not yet been described in other adenoma subtypes and represent a new MRI finding for sonic hedgehog hepatocellular adenoma.

Higher Expressions of SHH and AR Are Associated with a Positive Receptor Status and Have Impact on Survival in a Cohort of Croatian Breast Cancer Patients

Breast cancers (BC) are usually classified into four molecular subtypes according to the expression of estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors and proliferation marker Ki-67. Despite available anti-hormonal therapies and due to the inherent propensity of some subtypes to develop metastasis, there is a permanent need to discover new prognostic and predictive biomarkers, as well as therapeutic targets for BC. In this study, we used immunohistochemical staining to determine the expression of androgen receptor (AR) and sonic hedgehog protein (SHH), the main ligand of the Hedgehog-GLI (HH-GLI) signaling pathway, in 185 archival primary BC tissue samples and correlated it with clinicopathological characteristics, molecular subtypes, receptors statuses, and survival in a cohort of Croatian BC patients. Results showed that higher SHH and AR expressions were associated with positive receptor status, but increased SHH expression had a negative impact on survival in receptor-negative BCs. On the contrary, higher AR expression was mostly protective. However, multivariate analysis showed that only higher AR expression could be considered as an independent prognostic biomarker for poorer overall survival in triple-negative breast cancer patients (TNBC) (HR 10.9, 95% CI 1.43-83.67; p = 0.021), what could be Croatian population-related. SHH could be a potential target for treating TNBCs and HER2-enriched BCs, in cases where HH-GLI signaling is canonical (SHH-dependent).

Impaired Cerebellar Maturation, Growth Restriction, and Circulating Insulin-Like Growth Factor 1 in Preterm Rabbit Pups

Cerebellar growth is impeded following very preterm birth in human infants and the observed reduction in cerebellar volume is associated with neurodevelopmental impairment. Decreased levels of circulating insulin-like growth factor 1 (IGF-1) are associated with decreased cerebellar volume. The relationship between preterm birth, circulating IGF-1, and key cell populations supporting cerebellar proliferation is unknown. The aim of this study was to evaluate the effect of preterm birth on postnatal growth, circulating IGF-1, and cerebellar maturation in a preterm rabbit pup model. Preterm rabbit pups (PT) were delivered by cesarean section at day 29 of gestation, cared for in closed incubators with humidified air, and gavage fed with formula. Control term pups (T) delivered by spontaneous vaginal delivery at day 32 of gestation were housed and fed by their lactating doe. In vivo perfusion-fixation for immunohistochemical evaluation of cerebellar proliferation, cell maturation, and apoptosis was performed at repeated time points in PT and T pups. Results show that the mean weight of the pups and circulating IGF-1 protein levels were lower in the PT group at all time points (p < 0.05) than in the T group. Postnatal weight development correlated with circulating IGF-1 (r2 = 0.89) independently of gestational age at birth and postnatal age. The proliferative (Ki-67-positive) portion of the external granular layer (EGL) was decreased in the PT group at postnatal day 2 (P2) compared to in the T group (p = 0.01). Purkinje cells exhibited decreased calbindin staining at P0 (p = 0.003), P2 (p = 0.004), and P5 (p = 0.04) in the PT group compared to in the T group. Staining for sonic hedgehog was positive in neuronal EGL progenitors and Purkinje cells at early time points but was restricted to a well-defined Purkinje cell monolayer at later time points. Preterm birth in rabbit pups is associated with lower circulating levels of IGF-1, decreased postnatal growth, and decreased cerebellar EGL proliferation and Purkinje cell maturation. The preterm rabbit pup model exhibits important characteristics of human preterm birth, and may thus be suitable for the evaluation of interventions aiming to modify growth and cerebellar development in the preterm population.