Hepatic tumors of vascular origin: imaging appearances

Hepatic Angiosarcomas With Sinusoidal Growth Patterns

Hepatic angiosarcomas are aggressive malignant tumors of the liver with variable morphology. One of the rare morphologies is that of the sinusoidal growth pattern, which is challenging to diagnose because of its subtle imaging and morphologic findings. This retrospective study characterizes the clinical, histologic, and immunohistochemical features of sinusoidal hepatic angiosarcomas. Thirteen cases were included in the study, comprising 12 (92.3%) needle core biopsies and 1 wedge biopsy; one of the needle biopsies also had a subsequent resection specimen available for review. Multiple biopsies were needed to make the diagnosis in 4 cases. At least moderate sinusoidal dilatation was seen in 53.8% of cases. Increased cellularity within the sinusoids was seen at both low-power and high-power magnification (69.2% and 84.6%, respectively). Cytologic atypia ranged from mild to marked. Multinucleated tumor cells were present in most cases (10/13 cases) but were often sparse. Mitotic activity was identified in 5/13 cases. ERG immunostains were more reliable than CD31 and CD34 in identifying the tumor cells. Ki-67 proliferative index ranged from 5% to 30%. p53 immunostains were available in 9 cases and c-MYC in 7 cases; they were positive in 62.5% and 33.3% of cases, respectively and had a mutually exclusive staining pattern. In summary, this rare pattern of hepatic angiosarcoma is challenging to diagnose but has distinctive morphologic findings that can be supplemented with immunostains to establish the diagnosis.

MRLA-Net: A tumor segmentation network embedded with a multiple receptive-field lesion attention module in PET-CT images

The tumor image segmentation is an important basis for doctors to diagnose and formulate treatment planning. PET-CT is an extremely important technology for recognizing the systemic situation of diseases due to the complementary advantages of their respective modal information. However, current PET-CT tumor segmentation methods generally focus on the fusion of PET and CT features. The fusion of features will weaken the characteristics of the modality itself. Therefore, enhancing the modal features of the lesions can obtain optimized feature sets, which is extremely necessary to improve the segmentation results. This paper proposed an attention module that integrates the PET-CT diagnostic visual field and the modality characteristics of the lesion, that is, the multiple receptive-field lesion attention module. This paper made full use of the spatial domain, frequency domain, and channel attention, and proposed a large receptive-field lesion localization module and a small receptive-field lesion enhancement module, which together constitute the multiple receptive-field lesion attention module. In addition, a network embedded with a multiple receptive-field lesion attention module has been proposed for tumor segmentation. This paper conducted experiments on a private liver tumor dataset as well as two publicly available datasets, the soft tissue sarcoma dataset, and the head and neck tumor segmentation dataset. The experimental results showed that the proposed method achieves excellent performance on multiple datasets, and has a significant improvement compared with DenseUNet, and the tumor segmentation results on the above three PET/CT datasets were improved by 7.25%, 6.5%, 5.29% in Dice per case. Compared with the latest PET-CT liver tumor segmentation research, the proposed method improves by 8.32%.

[18F]FAPI PET/CT in the evaluation of focal liver lesions with [18F]FDG non-avidity

PURPOSE

This prospective study was aimed to investigate the potential utility of [¹⁸F]fibroblast activation protein inhibitor (FAPI) PET/CT for evaluating focal liver lesions (FLLs) with [¹⁸F]FDG non-avidity.

METHODS

From January 2021 to March 2022, this prospective study included 80 FLLs that were not avid on [¹⁸F]FDG PET/CT from 37 patients, then underwent [¹⁸F]FAPI PET/CT. All patients with FLL(s) with biopsy-proof or follow-up confirmation were categorized into four subgroups (20 hepatocellular carcinomas [HCCs]/5 non-HCC malignancies/4 inflammatory FLLs/8 benign noninflammatory FLLs). The diagnostic value of [¹⁸F]FAPI for detecting liver malignancy was determined by visual evaluation. Differences in the maximum standardized uptake value (SUV_max) and lesion-to-background ratio (LBR) obtained from [¹⁸F]FAPI PET/CT among the four subgroups were analyzed by semiquantitative analysis.

RESULTS

Among the thirty-seven enrolled participants (34 males; median age 57 years, range 48-67 years), on visual evaluation, the sensitivity, specificity, and accuracy of [¹⁸F]FAPI PET for detecting liver malignancy in the patient-based analysis were 96.0% (24/25), 58.3% (7/12), and 83.8% (31/37), respectively. On semiquantitative analysis, the SUV_max and LBR of [¹⁸F]FAPI PET in liver malignancy (33 HCC lesions; 19 non-HCC malignant lesions) were significantly higher than those in 11 benign noninflammatory FLLs [HCC: SUV_max: 6.4 vs. 4.5, P = 0.017; LBR: 5.1 vs. 1.5, P = 0.003; non-HCC: SUV_max: 5.5 vs. 4.5, P = 0.008; LBR: 4.4 vs. 1.5, P = 0.042]. Notably, there was no significant difference in the SUV_max of [¹⁸F]FAPI PET between 33 HCC lesions and 17 inflammatory FLLs (6.4 vs. 8.2, P = 0.37), but the LBR of [¹⁸F]FAPI PET in HCC were significantly lower than that in inflammatory FLLs (5.1 vs. 9.1, P = 0.003).

CONCLUSIONS

[¹⁸F]FAPI PET/CT shows high sensitivity in detecting HCC and non-HCC malignancy with [¹⁸F]FDG non-avidity. [¹⁸F]FAPI might be a promising radiopharmaceutical for the differential diagnosis of benign noninflammatory FLLs and liver malignancy with [¹⁸F]FDG non-avidity.

Imaging Findings of Hepatic Ewing's Sarcoma on Computed Tomography and Gadobenate Dimeglumine-enhanced Magnetic Resonance Imaging: A Case Report and Literature Review

Ewing's sarcoma (ES) is a tumor that often occurs in the long bones and rarely arises from visceral organs primarily. Here, we report a case of primary hepatic ES, discuss its computed tomography (CT) and gadobenate dimeglumine-enhanced magnetic resonance (MRI) features. This is the first Chinese and fifth primary hepatic ES case reported, based on a literature review. Imaging examinations showed that the tumor was solid, with necrosis and hemorrhage. Contrast-enhanced images showed that the tumor was hypervascular and especially had heterogeneous signal intensity on hepatobiliary phase MRI images. Intratumoral vessels and vascular invasion were also present.

Clinical characteristics and CT features of hepatic epithelioid haemangioendothelioma and comparison with those of liver metastases

BACKGROUND

To analyse clinical characteristics and computer tomography (CT) findings of hepatic epithelioid haemangioendothelioma (HEH) and to determine differential features compared with liver metastasis (LM).

METHODS

This retrospective study included 80 patients with histopathologically confirmed HEH (n = 20) and LM (n = 60) of different primary tumours who underwent dynamic contrast-enhanced CT scans. CT findings included the location, contour, size, number, margin, and density of lesions, the patterns and degree of contrast enhancement of lesions, vascular invasion and changes in other organs. The enhancement ratio (ER) and tumour-to-normal parenchyma ratio (TNR) were calculated. Receiver operating characteristic curves (ROCs) were used to determine areas under the curve (AUCs).

RESULTS

About 65% of HEH lesions were located in submarginal areas. Significant differences were observed between HEH and LM patients in age, sex, and tumour marker positivity (p < 0.05). HEH showed minimal to slight enhancement, thin ring-like enhancement in arterial phase, and slight, homogeneous, progressive enhancement in the portal phase. HEH presented capsule retraction, and the "target" sign and the "lollipop" sign were significantly more frequent than in LM (p < 0.05). The ER and TNR in the arterial phase of HEH were lower than those of LM (p < 0.05). AUCs of ER and TNR in the arterial phase were 0.74 and 0.73, respectively.

CONCLUSION

Lesions in subcapsular locations, capsular retraction, slight and thin ring-like enhancement, "target" and "lollipop" signs and lower ER and TNR in the arterial phase may represent important features of HEH compared with LM.

Non-invasive diagnosis and follow-up of primary malignant liver tumours

Among a wide range of malignant liver tumours, hepatocellular carcinoma (HCC) developed on a background of cirrhosis represents the most frequent clinical situation. In this setting, HCC is one of the rare solid tumours for which histological confirmation is not mandatory. The convergence of multiple arguments obtained by non-invasive parameters using radiological findings allows to avoid liver biopsy in a large proportion of patients when a diagnosis of underlying cirrhosis is ascertained. Conversely, in case of atypical presentation or in order to exclude other rare malignant tumours mostly developed in the absence of cirrhosis, liver biopsy will then be essential. Based on typical radiological patterns described by contrast-enhanced imaging, numerous clinical guidelines have endorsed non-invasive diagnosis, staging and monitoring of HCC patients under treatment since 20 years. These algorithms have evolved over the years, taking into account progress in radiological technology and advances in curative or palliative procedures. Large cohort studies have also helped to refine diagnostic criteria and prognostication in the setting of complex therapeutic strategy. Unsupervised multi-analysis approaches both at the biological and radiological levels will in the future enrich the panel of non-invasive markers useful in clinical practice to manage HCC and other malignant tumours.

Primary hepatic malignant vascular tumors: a follow-up study of imaging characteristics and clinicopathological features

Background

Owing to its low incidence, there is insufficient clinical awareness and diagnostic experience with primary hepatic malignant vascular tumors (PHMVTs). The aim of our study was to investigate the imaging and clinicopathological features of patients with PHMVTs and analyze the clinicopathological correlations.

Methods

We retrospectively analyzed 42 patients who had pathologically confirmed PHMVT during the period from June 2012 to December 2019 and enrolled them in our study. The computed tomography (CT) and magnetic resonance (MR) images and pathological findings of each patient were recorded.

Results

There were more female (29/42) than male patients. The imaging features of primary hepatic angiosarcoma (PHA) (n = 11) included ill-defined margins (11/11, 100%), necrosis (5/11, 45%), calcification (3/11, 27%) and “slow in-slow out” centripetal enhancement (7/11, 64%). Patients with epithelioid hemangioendothelioma (EHE) (n = 15) presented with ill-defined margins (15/15, 100%), necrosis (6/15, 40%), calcification (2/15, 13%), “fast in-slow out” centripetal enhancement (10/15, 67%), halo sign (15/15, 100%), pseudocapsule sign (4/15, 27%), lollipop sign (2/15, 13%) and capsule retraction sign (2/15, 13%). Patients with malignant hemangiopericytoma (MHP) (n = 3) showed ill-defined margins (3/3, 100%), necrosis (3/3, 100%) and “fast in-slow out” progressive enhancement (3/3, 100%). Infantile hemangioendotheliomas (IHEs) (n = 13) were defined by ill-defined margins (7/13, 54%), necrosis (8/13, 62%), calcification (5/13, 38%) and “fast in-slow out” centripetal enhancement (13/13, 100%). Immunohistochemistry showed strong positive expression of CD31, CD34, ERG, FaVIII and FLI-1. Patients with IHE (96 months) and EHE (88 months) had the longest survival times, followed by those with MHP (23 months), while patients with PHA (15 months) had the shortest survival time.

Conclusion

On CT and MR images, most PHMVTs were ill-defined, heterogeneous, hypervascular masses with centripetal progressive enhancement and possibly calcification, especially in female patients. The prognosis of patients with PHMVT was associated with the pathological type of the tumor.

Malignant hepatic vascular tumors in adults: Characteristics, diagnostic difficulties and current management

Malignant vascular tumors of the liver include rare primary hepatic mesenchymal tumors developed in the background of a normal liver parenchyma. Most of them are detected incidentally by the increased use of performing imaging techniques. Their diagnosis is challenging, involving clinical and imaging criteria, with final confirmation by histology and immunohistochemistry. Surgery represents the mainstay of treatment. Liver transplantation (LT) has improved substantially the prognosis of hepatic epithelioid hemangioendothelioma (HEHE), with 5-year patient survival rates of up to 81%, based on the European Liver Intestine Transplantation Association-European Liver Transplant Registry study. Unfortunately, the results of surgery and LT are dismal in cases of hepatic angiosarcoma (HAS). Due to the disappointing results of very short survival periods of approximately 6-7 mo after LT, because of tumor recurrence and rapid progression of the disease, HAS is considered an absolute contraindication to LT. Recurrences after surgical resection are high in cases of HEHE and invariably present in cases of HAS. The discovery of reliable prognostic markers and the elaboration of prognostic scores following LT are needed to provide the best therapeutic choice for each patient. Studies on a few patients have demonstrated the stabilization of the disease in a proportion of patients with hepatic vascular tumors using novel targeted antiangiogenic agents, cytokines or immunotherapy. These new approaches, alone or in combination with other therapeutic modalities, such as surgery and classical chemotherapy, need further investigation to assess their role in prolonging patient survival. Personalized therapeutic algorithms according to the histopathological features, behavior, molecular biology and genetics of the tumors should be elaborated in the near future for the management of patients diagnosed with primary malignant vascular tumors of the liver.

Vascular tumours of the liver: a particular story

Vascular tumours of the liver represent an underrated chapter of medical and surgical hepatology. These tumours cover a wide spectrum ranging from the frequent and most benign hepatic haemangioma (HH), via the rare and intermediately aggressive hepatic epithelioid haemangioendothelioma (HEHE) to the rare and most malignant hepatic haemangiosarcoma (HHS). In contrast to the treatment algorithms for hepatocellular and cholangiocellular cancer, the diagnostic and therapeutic approaches to HEHE and HHS are not well developed. The related uncertainty is explained by their rare occurrence and their protean clinical, morphological (imaging) and histopathological presentation and behaviour. This article gives an update about these particular tumours based on the analysis of the recent literature and of the studies on vascular tumours published by the European Liver Intestine Transplantation Association (ELITA)-European Liver Transplant Registry (ELTR). It focuses also on the place of liver transplantation (LT) in the respective therapeutic algorithms. The differential diagnosis between these vascular and other tumour types may be very difficult. Correct diagnosis is of utmost importance and is based on a high index of clinical suspicion and on the integration of clinical, radiological, histological [including immunohistochemistry (IHC) and molecular biology findings]. Surgery, be it partial or total hepatectomy (LT), should be proposed whenever possible, because it is the therapeutic mainstay. In HEHE, LT provides excellent results, with long-term disease-free survivals (DFS) reaching 75%. Good results can be obtained even in case of (frequent) extrahepatic spread. Based on the extensive ELITA-ELTR study a HEHE-LT prognostic score has been proposed in order to estimate the risk of recurrence after LT. In contrast, results of surgery and LT are extremely poor for HHS, for the almost invariably rapid recurrence (within 6 months) and related death within 2 years. LT remains a contraindication for HHS. Due to the still important recurrence rate after surgical resection (25% in HEHE and almost 100% in HHS), there is an urgent need to develop pharmacological treatments targeting angiogenic and non-VEGF angiogenic pathways. To date, some prospective pilot studies and case reports have shown some short-term stabilisation of the disease in small groups of patients. In order to make progress, combination of surgery, anti-angiogenic and immunotherapy seems worthwhile. To complete the panel of vascular liver tumours, infantile haemangioendothelioma, haemangiopericytoma, nodular regenerative hyperplasia (NRH) and hepatic small vessel neoplasms (HSVN) are also discussed.