Hepatic mesenchymal hamartoma and undifferentiated embryonal sarcoma of the liver: a pathologic review

Treatment of Undifferentiated Embryonal Sarcoma of the Liver in Children

Undifferentiated embryonal sarcoma of the liver is a rare mesenchymal tumor with a highly malignant potential. It occurs almost exclusively in the pediatric population and typically has a poor outcome. Although previous studies have reported dismal prognoses, recent advances in combined treatment modalities, e.g., surgery and chemotherapy, have given cause for optimism. Even in those diseases not amenable to complete surgical resection or refractory diseases, other treatment modalities, such as liver transplant, have yielded promising results. This paper provides a review of the current treatment modalities for hepatic undifferentiated embryonal sarcoma in children.

First report of spontaneous hepatic fibrosarcoma in a white-tufted marmoset (Callithrix jacchus) kept in captivity

Reports of sarcomas in nonhuman primates are scarce and, specifically, primary hepatic sarcomas are rare, as in humans. This is the first report of an aggressive hepatic fibrosarcoma in a young adult Callithrix jacchus. The final postmortem diagnosis was obtained by means of immunohistochemical analysis, which confirmed the tumor histogenesis.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part II

Malignant focal liver lesions (FLLs) represent various kinds of epithelial and mesenchymal tumors. In pediatric patients, the understanding of pediatric liver diseases and associated imaging manifestations is essential for making accurate diagnosis and differential diagnosis. This paper will discuss the latest knowledge of the common pediatric malignant FLLs, including undifferentiated embryonal sarcoma, rhabdomyosarcoma, epithelioid hemangioendothelioma, angiosarcoma, and malignant rhabdoid tumor. Medical imaging features are not only helpful for clinical diagnosis, but can also be useful in the evaluation and follow-up of pre- and post-treatment. The future perspectives of contrast-enhanced ultrasound (CEUS) enhancement patterns of FLLs in pediatric patients are also mentioned.

Mesenchymal Neoplasms of the Liver

Mesenchymal neoplasms of the liver can be diagnostically challenging, particularly on core needle biopsies. Here, I discuss recent updates in neoplasms that are specific to the liver (mesenchymal hamartoma, undifferentiated embryonal sarcoma, calcifying nested stromal-epithelial tumor), vascular tumors of the liver (anastomosing hemangioma, hepatic small vessel neoplasm, epithelioid hemangioendothelioma, angiosarcoma), and other tumor types that can occur primarily in the liver (PEComa/angiomyolipoma, inflammatory pseudotumor-like follicular dendritic cell sarcoma, EBV-associated smooth muscle tumor, inflammatory myofibroblastic tumor, malignant rhabdoid tumor). Lastly, I discuss metastatic sarcomas to the liver, as well as pitfalls presented by metastatic melanoma and sarcomatoid carcinoma.

Uncommon Benign Neoplasms and Pseudotumors of the Liver

CONTEXT.—

The most common benign hepatic mass-forming lesions often display fairly specific imaging characteristics, whereas less familiar, rarer benign neoplasms and pseudotumors may pose a diagnostic challenge in clinical, radiology, and pathology practice because of either their rarity or their unusual features.

OBJECTIVE.—

To review a selection of pseudotumors and unusual benign hepatic neoplasms encountered in consultation practices with a focus on nonepithelial tumors.

DATA SOURCES.—

Sources include English-language literature and personal experiences.

CONCLUSIONS.—

Several benign conditions (namely, segmental atrophy, infections, immunoglobulin G4 [IgG4]-related sclerosing disease, angiomyolipoma, mesenchymal hamartoma, and various vascular lesions) can lead to formation of hepatic masses. Because of their rarity and underrecognition, such lesions are often diagnostically challenging. Awareness of hepatic pseudotumors and various rare hepatic neoplasms and their potential mimics can forestall misdiagnosis and inappropriate management.

Hepatobiliary mucinous cystic neoplasms and mimics

This review will provide an overview of hepatobiliary mucinous cystic neoplasms and their mimics such as complex appearing benign cysts, intraductal papillary neoplasm of bile ducts, choledochal cysts, infectious cysts, and other cystic neoplasms. Preoperative imaging, particularly abdominal MRI with MRCP, plays a key role in differentiating these entities which differ widely in management. Familiarity with the differentiating imaging features of mucinous cystic neoplasms and their mimics allows radiologists to provide management-guiding reports.

Case Report of Undifferentiated Hepatic Embryonal Sarcoma with Mesenchymal Hamartoma: A Rare Entity

Undifferentiated embryonal sarcoma (UES) is a highly malignant hepatic neoplasm, which occurs mostly in pediatric population. There is a link between embryonal sarcoma and mesenchymal hamartoma as evidenced by clinicopathological overlap and similar genetic abnormality. Here, we report a case of UES in a young female in a background of mesenchymal hamartoma of liver.

Liver Transplant for Adult Recurrent Hepatic Mesenchymal Hamartoma and a Feasible Treatment Modality: A Case Report and Literature Review

BACKGROUND

Adult hepatic mesenchymal hamartoma (HMH) is an extremely rare hepatic tumor. Recurrence following complete resection is uncommon. Liver transplantation (LT) is described as a possible treatment option in nonresectable HMH. We conducted a systematic review investigating LT in adult HMH followed by a case report describing evidence of extensive recurrence following complete resection of large right-sided HMH requiring LT.

CASE REPORT

A 46-year-old woman with symptomatic large right-hepatic HMH underwent right hemi-hepatectomy with histologic evidence of complete resection. Two and a half years postresection, she presented with abdominal pain and distension; imaging revealed large multi-septated hepatic cystic lesions within the liver suggestive of extensive recurrence of disease with concerns of malignant sarcomatous transformation. After a multidisciplinary team discussion, the lesion was deemed unresectable and the patient was referred for LT. Findings on transplantation included giant multiple hepatic cystic lesions occupying the entire abdomen and histopathological analysis confirmed recurrent HMH with no malignancy. The 6-month follow-up was unremarkable with no signs of postoperative complications or rejection.

CONCLUSION

We identified only 3 reported adult unresectable HMH cases in the English literature requiring LT, with good clinical outcome and no rejection on a 1-year follow-up. To our knowledge, we report the first recurrent HMH that required LT in the English literature. Current evidence suggests possible malignant sarcomatous transformation of those lesions. No guidelines exist on postresection surveillance for HMH; however, given their malignant potential, we suggest a benefit of imaging-based surveillance following HMH resection. Offering LT for nonresectable or recurrent HMH is a feasible treatment modality with a reported good outcome.

Imaging of fibropolycystic liver disease

Fibropolycystic liver diseases (FLDs) make up a rare spectrum of heritable hepatobiliary diseases resulting from congenital ductal plate malformations (DPMs) due to the dysfunction of proteins expressed on the primary cilia of cholangiocytes. The embryonic development of the ductal plate is key to understanding this spectrum of diseases. In particular, DPMs can result in various degrees of intrahepatic duct involvement and a wide spectrum of cholangiopathies, including congenital hepatic fibrosis, Caroli disease, polycystic liver disease, and Von Meyenberg complexes. The most common clinical manifestations of FLDs are portal hypertension, cholestasis, cholangitis, and (in rare cases) cholangiocarcinoma. This article reviews recent updates in the pathophysiology, imaging, and clinical management of FLDs.

Benign focal liver lesions: The role of magnetic resonance imaging

Liver lesions are common findings in radiologists’ daily routine. They are a complex category of pathology that range from solitary benign lesions to primary liver cancer and liver metastases. Benign focal liver lesions can arise from different liver cell types: Epithelial (hepatocytes and biliary cells) and nonepithelial (mesenchymal cells). Liver magnetic resonance imaging (MRI) is a fundamental radiological method in these patients as it allows with its multiparametric approach optimal non-invasive tissue characterization. Furthermore, advanced liver MRI techniques such as diffusion-weighted imaging and hepatobiliary contrast agents have improved the detection of focal liver lesions and can be highly effective in differentiating pseudotumor from tumors, as well as benign from malignant lesions, and can also be used for differential diagnosis. Although histological examination can be useful in making a definitive diagnosis, MRI is an important modality in the diagnosis of liver lesions with a significant impact on patient care. This aim of this review is to provide a comprehensive overview of benign liver lesions on MRI.

DICER1-associated hepatic cystic neoplasm with pleuropulmonary blastoma-like features: a novel clinicopathologic diagnosis

This report documents a unique multicystic neoplasm of the liver in an 8-month-old boy with a heterozygous germline pathogenic DICER1 variant. This neoplasm, initially considered most likely a mesenchymal hamartoma based on imaging, demonstrated the characteristic histologic pattern of embryonal rhabdomyosarcoma residing in the subepithelial or cambium layer-like zone of the epithelial-lined cysts. Thus, although the differential diagnosis includes mesenchymal hamartoma, a young child with a multicystic mass lesion in the liver, lung, or kidney should both raise the possibility of a germline pathogenic DICER1 variant and also not be mistaken for one of the other hepatic neoplasms of childhood.

New insights in gastrointestinal "pediatric" neoplasms in adult patients: pancreatoblastoma, hepatoblastoma and embryonal sarcoma of the liver. A practical approach by GIPPI-GIPAD Groups

Pediatric solid neoplasms are rare and very different from those observed in adults. The majority of them are referred to as embryonal because they arise as a result of alterations in the processes of organogenesis or normal growth and are characterized by proliferation of primitive cells, reproducing the corresponding tissue at various stages of embryonic development. This review will focus on embryonal gastrointestinal pediatric neoplasms in adult patients, including pancreatoblastoma, hepatoblastoma, and embryonal sarcoma of the liver. Although they are classically considered pediatric neoplasms, they may (rarely) occur in adult patients. Hepatoblastoma represents the most frequent liver neoplasm in the pediatric population, followed by hepatocellular carcinoma and embryonal sarcoma of the liver; while pancreatoblastoma is the most common malignant pancreatic tumor in childhood. Both in children and adults, the mainstay of treatment is complete surgical resection, either up front or following neoadjuvant chemotherapy. Unresectable and/or metastatic neoplasms may be amenable to complete delayed surgery after neoadjuvant chemotherapy. However, these neoplasms display a more aggressive behavior and overall poorer prognosis in adults than in children, probably because they are diagnosed in later stages of diseases.

Magnetic resonance imaging of pediatric liver tumors

Liver tumors in children can be benign or malignant. Although several clinical factors are important in the evaluation of these lesions, MRI is particularly important for lesion characterization and tumor staging. In children, use of a hepatobiliary contrast agent is recommended to evaluate a known or suspected liver lesion. In this review, we discuss the most common benign and malignant pediatric liver tumors, including vascular tumors, mesenchymal hamartoma, focal nodular hyperplasia, hepatocellular adenoma, hepatoblastoma, hepatocellular carcinoma, fibrolamellar hepatocellular carcinoma, undifferentiated embryonal sarcoma and metastases, with emphasis on relevant clinical information and imaging appearance at MRI using hepatobiliary agents.

A large undifferentiated sarcoma of the liver in a 13-year-old girl treated with anatomical resection: a case report and review of the literature

Background

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare liver tumor accounting for 6–13% of primary liver tumors. Accurate preoperative diagnosis is difficult, with a rather high misdiagnosis rate. Herein, we reported a very large UESL treated with anatomical resection. Our case is amongst the largest pediatric UESLs in the literature.

Case presentation

Herein, we report a 13-year-old girl presenting with right upper quadrant abdominal pain, postprandial vomiting, and abdominal distention, in which radiographic imaging demonstrated a huge UESL (28 × 20 × 12 cm). The patient was treated with partial hepatectomy and the 5 kg tumor was removed. The patient was discharged in good condition, with no significant complaints in her follow-up.

Conclusions

Although different treatment strategies have been reported for UESL cases, anatomical resection is still the main treatment approach, especially for large tumors.

Fetal mesenchymal hamartoma of the liver: A case report and literature review

This paper reports the diagnosis and treatment process of a case of fetal mesenchymal hamartoma of the liver (MHL), and reviews the previous literature reports. At 38⁺² weeks of gestation, prenatal ultrasound found a well bound mixed solid and cystic mass, which was located at the lower edge of the right lobe of the liver and in front of the right kidney of the fetus, but the source and nature of the mass were not clear by ultrasound. Due to the approaching due date, the fetus showed no other abnormal symptoms, and no special treatment was given with the consent of the family members. A female fetus was delivered weighing 3,520 g at 39 weeks. An exploratory laparotomy was performed on the eighth day after delivery. During the operation, it was found that the tumor originated from the fifth, sixth and seventh hepatic segment and the corresponding hepatic segments were removed. Recovery was uneventful and the infant was discharged on the 6th day after surgery. Follow-up at 2 years showed a thriving young girl, and there was no tumor recurrence.

DICER1 tumor predisposition syndrome: an evolving story initiated with the pleuropulmonary blastoma

DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation.

Adult versus paediatric undifferentiated embryonal sarcoma of the liver: a SEER database analysis

BACKGROUND

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare liver tumour that occurs mainly in children. Herein, we aimed to identify any differences in clinical characteristics and survival between adult and paediatric patients with UESL.

METHODS

From 1975 to 2015 in the Surveillance, Epidemiology and End Results (SEER) database, patients diagnosed with UESL were identified and divided into paediatric (<18 years) and adult (≥18 years) groups. We then compared the clinical characteristics, management, and overall survival (OS) of adults and children diagnosed with UESL.

RESULTS

We analysed 113 patients with UESL (81 children and 32 adults). UESL was significantly more common in adult male than paediatric male patients (71.9% vs. 48.2%; P = 0.022). When compared to adult patients, paediatric patients were more likely to receive chemotherapy (93.8% vs. 65.6%; P < 0.001). Adults had a significantly worse OS than paediatric patients (5-year OS, 30.0% vs. 81.2%; P < 0.001). Univariate analysis found that adult age, surgical therapy and chemotherapy were associated with OS. Multivariate analysis revealed that adult age, SEER summary stage and surgical therapy were independent prognostic factors for OS.

CONCLUSIONS

UESL had a male predominance among adult patients. Moreover, the prognosis of adult patients with UESL was significantly worse than that of paediatric patients. Surgery and chemotherapy should be considered in the treatment of patients with UESL.

Intraoperative Transesophageal Echocardiography to Monitor for Pulmonary Emboli in a Pediatric Patient Undergoing Undifferentiated Embryonal Sarcoma of the Liver Resection

A minimally invasive monitoring technique, intraoperative transesophageal echocardiography (TEE), has been utilized to provide real-time data on volume status and ventricular function in patients undergoing liver transplantation. In this case, TEE was utilized in an 8-year-old female undergoing undifferentiated embryonal sarcoma of the liver resection to monitor for pulmonary emboli, particularly a saddle embolus. In addition to visualization of cardiac structures, TEE can also be utilized to monitor the liver, lungs, spleen, and kidneys. Monitoring for echocardiographic findings of pulmonary embolism in this high-risk patient was an integral part of effective intraoperative management.

Clinicopathological study of hepatic mesenchymal hamartoma and undifferentiated embryonal sarcoma of the liver: a single center study from Iran

Background

Undifferentiated embryonal sarcoma of liver (UESL) and hepatic mesenchymal hamartoma (HMH) are two rare entities which mainly affect the pediatric population. The aim of this investigation was to provide a comprehensive overview of the clinicopathologic characteristics of the patients diagnosed with these two conditions in a tertiary referral center in Iran.

Methods

In this retrospective study patients diagnosed with UESL or HMH between 2012 and 2020 were studied. A comprehensive histopathologic evaluation of the cases along with immunohistochemistry evaluation using a panel of antibodies was conducted. Furthermore, clinical, paraclinical, and treatment data and follow up information was collected.

Results

A total of 16 patients (8 UESL, 8 HMH) were studied in this investigation. Patients with UESL had a significantly (p = 0.002) higher age at diagnosis compared with those with HMH. Histologically, UESL cases were characterized by anaplastic cells with eosinophilic cytoplasm and bizarre nuclei and frequent atypical mitosis and spindling in a myxoid stroma while disordered arrangement of hepatic parenchyma, bile ducts, and primitive mesenchyme was seen in HMH. Furthermore, small round cells and extramedullary hematopoiesis were seen in 2 UESL and 3 HMH cases, respectively. Concurrent HMH was also seen in two UESL cases. Immunohistochemistry panel showed positive staining for Vimentin, Glypican-3, Desmin, CD56, CD10, and BCL2 in UESL cases and immunoreactivity for Vimentin, HepPar 1, Glypican-3, SMA, CD56, BCL2, and CD34 in various components of HMH.

Conclusions

In this study, the clinicopathologic features of UESL and HMH cases are presented. We also evaluated the utility of an immunohistochemistry panel in the diagnosis of these two rare entities and suggested novel markers. Our study corroborated the findings of previous investigations and expanded the clinicopathologic features of these two rare entities with diagnostic and potential therapeutic implications.

Pediatric Primary Hepatic Tumors: Diagnostic Considerations

The liver is the third most common site of abdominal tumors in children. This review article aims to summarize current evidence surrounding identification and diagnosis of primary hepatic tumors in the pediatric population based upon clinical presentation, epidemiology, and risk factors as well as classical imaging, histopathological, and molecular diagnostic findings. Readers will be able to recognize the features and distinguish between benign and malignant hepatic tumors within different age groups.

Undifferentiated embryonal sarcoma of the liver: Clinical characteristics and outcomes

BACKGROUND

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare liver malignancy originating from primary mesenchymal tissue. The clinical manifestations, laboratory tests, and imaging examinations of the disease lack specificity and the preoperative misdiagnosis rate is high. The overall prognosis is poor and survival rate is low.

AIM

To investigate the diagnosis, treatment, and prognosis of UESL.

METHODS

We performed a retrospective, single-center cohort study in Shengjing Hospital of China Medical University, which is a central hospital in northeast China. From 2005 to 2017, we recruited 14 patients with pathologically confirmed UESL. We analyzed the clinical manifestations, laboratory tests, imaging examinations, pathological examinations, therapy, and prognosis of these patients.

RESULTS

There were nine males and five females aged 2-60 years old included in the study. The major initial symptoms were abdominal pain (71.43%) and fever (57.14%). Preoperative laboratory tests revealed that seven patients had increased leukocyte levels, four showed a decrease in hemoglobin levels, seven patients had increased glutamyl transpeptidase levels, nine had increased lactate dehydrogenase levels, and three showed an increase in carbohydrate antigen 199. There was no difference in the rate of misdiagnosis in preoperative imaging examinations of UESL between adults and children (6/6 vs 5/8, P = 0.091). The survival rate after complete resection was 6/10, while that after incomplete resection was 0/4 (P = 0.040), suggesting that complete resection is important to improve survival rate. In total, five out of the eight children achieved survival. During the follow-up, the maximum survival time was shown to be 11 years and minimum survival time was 6 mo. Six adult patients relapsed late after surgery and all of them died.

CONCLUSION

Preoperative imaging examination for UESL has a high misdiagnosis rate. Multidisciplinary collaboration can improve the diagnostic accuracy of UESL. Complete surgical resection is the first choice for treatment of UESL.