Nested stromal epithelial tumor of the liver in Beckwith-Wiedemann syndrome

Mesenchymal Tumors of the Liver: An Update Review

Hepatic mesenchymal tumors (HMTs) are non-epithelial benign and malignant tumors with or without specific mesenchymal cell differentiation. They are relatively uncommon. Except for mesenchymal hamartoma, calcified nested stromal-epithelial tumor, and embryonal sarcoma, most mesenchymal lesions are not specific to the liver. Pathologists face challenges in diagnosing HMTs due to their diverse morphologies and phenotypic variations. Accurate diagnosis is critical for directing appropriate patient care and predicting outcomes. This review focuses on mesenchymal tumors with a relative predilection for the liver, including vascular and non-vascular mesenchymal neoplasms. It provides a thorough and up-to-date overview, concentrating on clinical and pathological features, differential diagnosis, and diagnostic approaches.

"Update on pediatric primary liver tumors"

Liver masses are common in children, however primary malignant neoplasms are rare, representing only 1% of all pediatric cancers. Hepatocellular neoplasms are the most common primary liver malignancies and hepatoblastoma (HB) is the most frequently diagnosed. The incidence of HB, which is increasing, is approximately of 2 cases per million in the United States, followed by hepatocellular carcinoma (HCC). Pediatric primary liver tumors of mesenchymal origin are less common, except for benign vascular tumors (hemangiomas). Malignant mesenchymal neoplasms represent approximately 10-15% of all, the most common being embryonal sarcoma and malignant rhabdoid tumor. Malignant vascular tumors are rare, but epithelioid hemangioendothelioma (EHE) and angiosarcoma can be seen in children. The development and adoption of consensus diagnostic, therapeutic and risk-stratifying approaches for pediatric patients with malignant liver tumors has been historically challenged by their rarity and by their diverse clinical and histological appearance. On-going collaborative efforts of international consortia including the Children's Oncology Group (COG) in North America, the German Society of Paediatric Oncology and Haematology (GPOH), the Societe Internationale d' Oncologie Pediatrique Liver Tumor Study Group (SIOPEL) in Europe and the Japanese Liver Tumor group (JPLT), have made significant contributions to understanding the clinical and histopathological features, as well as the underlying biology of pediatric liver tumors, in particular HB. A new classification of pediatric liver tumors drafted at the international consensus meeting held in Los Angeles, has been incorporated in the recent WHO classification and is currently used by the PHITT (Paediatric Hepatic Malignancy International Tumour Trial) and other therapeutic protocols. This manuscript provides an overview of salient diagnostic features and updates in classification and molecular characterization for the most common pediatric primary liver neoplasms. It also includes a brief overview of other less common but relevant tumors, which should be considered in the differential diagnosis.

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.

Liver Transplantation for Unresectable Calcifying Nested Stromal Epithelial Tumor: Case Report With a 1-Year Follow-Up and Review of Literature

Introduction

Calcifying nested stromal epithelial tumor (CNSET) is an extremely rare diagnosis among patients treated for primary hepatic neoplasms. There are only 45 cases reported worldwide. Histopathological characteristics are well-demarcated nests of spindle and epithelioid cells in a dense desmoplastic stroma with variable calcification and ossification. It is mostly diagnosed in children and young females. Treatment strategies implemented for the management of CNSET include radiofrequency ablation, transarterial chemoembolization, surgical resection, adjuvant and neoadjuvant chemotherapy, and liver transplantation. Given the small number of available cases, there are still no established standards of treatment for this neoplasm.

Case Presentation

A 28-year-old female diagnosed with CNSET presented mild abdominal pain, with normal laboratory values. The tumor was initially deemed unresectable, therefore, the patient was disqualified from liver resection. Further deterioration of the patient's clinical condition and local tumor progression led to qualification for liver transplantation. The patient underwent liver transplantation 1 year following initial diagnosis and a 12 months recurrence-free period was observed. During the course of treatment, she did not receive systemic chemotherapy, radiotherapy, or loco-regional treatment.

Conclusion

Multiple strategies have been implemented for the treatment of CNSET, with liver resection providing the best outcomes. Transarterial chemoembolization, radiofrequency ablation, and radiotherapy are reported to be insufficient in the management of this tumor. Various chemotherapy regimens turned out to be ineffective as well. There have been only eight reported cases of patients undergoing liver transplantation for CNSET, with tumor recurrence in two cases. CNSET appears to be a neoplasm with low malignancy potential, although an aggressive progression has subsequently been reported. Further investigation is still required in this field.

Nested Stromal-Epithelial Tumor of the Liver: A Review

BACKGROUND

Nested stromal-epithelial tumor (NSET) is a rare liver tumor, which is most commonly seen in the pediatric age group. To the best of our knowledge, there has been no published review on this rare tumor in the English literature so far.

SUMMARY

In this review, we will discuss all the reported details of the published cases, including demography, clinical presentation, molecular histogenesis, imaging, gross pathology and histopathology, immunohistochemical findings, treatment modalities, and outcome of NSET of the liver.

KEY MESSAGE

Thirty-eight cases of NSET have been reported in the last 20 years in the English literature. This tumor produces a very large and calcified mass in the liver and characteristically can present as Cushing syndrome. NSET is a nonbiliary and nonhepatocytic tumor with biphasic differentiation into 2 components of epithelial and stromal cells. The epithelial cells are arranged as nests of mildly atypical epithelial cells with a few mitotic figures. The stromal component is composed of myofibroblasts and desmoplastic stroma which often shows ossification and calcification. Immunohistochemically, this tumor is positive for both epithelial and mesenchymal markers. The majority of the reported cases in the literature had benign behavior with an indolent course.

Calcifying Nested Stromal-Epithelial Tumor of the Liver: An Update and Literature Review

Calcifying nested stromal-epithelial tumor is a rare entity that has gone by a variety of names in the literature: ossifying malignant mixed epithelial and stromal tumor, ossifying stromal-epithelial tumor, and desmoplastic nested spindle cell tumor of the liver. To our knowledge, approximately 38 cases have been reported in the literature. The histogenesis is still largely unknown but histopathologically is characterized by nests of spindle and epithelioid cells in an organoid arrangement surrounded by a prominent dense myofibroblastic stroma with occasional psammomatous calcification and focal heterotopic ossification. Vascular invasion is rare and tumoral recurrence is uncommon with only a single reported case of metastasis leading to death. Treatment is mainly by surgical intervention with the role of chemotherapy seeming limited, but lack of data hinders a true recommendation. It is important to rule out other processes such as hepatoblastoma, calcified hemangioma, synovial sarcoma, metastatic gastrointestinal stromal tumor, desmoplastic small round cell tumor, among others, which appear similar radiographically and histopathologically.

Calcifying nested stromal epithelial tumor of the liver in a patient with Klinefelter syndrome: a case report and review of the literature

BACKGROUND

Calcifying nested stromal epithelial tumor (CNSET) is a primary neoplasm of the liver, characterized by well-demarcated nests consisting of spindle and epithelioid cells with calcification and bone formation. An association of Cushing syndrome with CNSET has drawn attention, but the origin of CNSET has not been clarified.

CASE PRESENTATION

We report here the case of a 20-year-old male with Klinefelter syndrome who underwent liver resection for an increasing liver tumor that was pathologically diagnosed with CNSET. He was postoperatively followed up and received several examinations, and recurrences and extrahepatic lymph node metastases were detected on the 64th day after surgery. Chemoembolization and chemotherapy were not effective, leading to tumor progression with development of progressive liver failure, and the patient finally died 164 days after hepatectomy.

CONCLUSIONS

This case suggests that an imbalance of hormones affects the genesis and progression of CNSET, and indicates the importance of closely following patients with CNSET by imaging with attention to hepatic recurrence and extrahepatic metastases.

Successful liver transplantation for non-resectable desmoplastic nested spindle cell tumor complicated by Cushing's syndrome

Desmoplastic spindle cell tumors of liver are rare tumors of low malignant potential characterized by well-demarcated nests of spindle and epithelioid cells in a dense desmoplastic stroma. While surgery remains the definitive treatment, there have been reports of tumor recurrence locally and metastasis which respond poorly to chemotherapy. Hepatic transplant has been attempted in cases of recurrence or large size of primary tumor. Long-term follow-up and imaging surveillance are required as these tumors have shown a tendency for recurrence many years after initial therapy.

Malignant tumors of the liver in children

This article aims to give an overview of pediatric liver tumors; in particular of the two most frequently occurring groups of hepatoblastomas and hepatocellular carcinomas. Focus lays on achievements gained through worldwide collaboration. We present recent advances in insight, treatment results, and future questions to be asked. Increasing international collaboration between the four major Pediatric Liver Tumor Study Groups (SIOPEL/GPOH, COG, and JPLT) may serve as a paradigm to approach rare tumors. This international effort has been catalyzed by the Children's Hepatic tumor International Collaboration (CHIC) formation of a large collaborative database. Interrogation of this database has led to a new universal risk stratification system for hepatoblastoma using PRETEXT/POSTTEXT staging as a backbone. Pathologists in this international collaboration have established a new histopathological consensus classification for pediatric liver tumors. Concomitantly there have been advances in chemotherapy options, an increased role of liver transplantation for unresectable tumors, and a web portal system developed at www.siopel.org for international education, consultation, and collaboration. These achievements will be further tested and validated in the upcoming Paediatric Hepatic International Tumour Trial (PHITT).

Desmoplastic nested spindle cell tumours and nested stromal epithelial tumours of the liver

Desmoplastic nested spindle cell tumour of liver (DNSTL), nested stromal-epithelial tumour (NSET) and calcifying nested stromal-epithelial tumour (CNSET) are recently described entities with similar morphology, immunohistochemistry and molecular genetics. These are rare entities with only three large case series described till date. These tumours commonly present in the paediatric age group. NSETs, in addition have been described to be associated with ectopic adrenocorticotropic hormone (ACTH) production and Cushingoid features. It is important to discuss this rare group of tumours with a low malignant potential as the most common radiological differential diagnosis is hepatoblastoma, which has a relatively poorer prognosis. Thus, a pathologist needs to keep this entity in mind, so as to offer a correct histological diagnosis.

CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis

β-catenin (CTNNB1) is a key regulatory molecule of the Wnt signaling pathway, which is important for tissue homeostasis and regulation of cell proliferation, differentiation, and function. Abnormal stabilization and nuclear accumulation of β-catenin as a consequence of missense mutations or alternative molecular mechanisms occurs at a high frequency in a variety of epithelial cancers. In mesenchymal neoplasia, the role of β-catenin has been traditionally considered limited to desmoid-type fibromatosis. However, the spectrum of β-catenin-driven (β-catenin-altered) neoplasia of mesenchymal origin has been steadily widening to include, in addition to desmoid tumors, a variety of benign and intermediate-biology neoplasms of soft tissue (intranodal palisaded myofibroblastoma), head and neck (juvenile nasopharyngeal angiofibroma and sinonasal hemangiopericytoma/glomangiopericytoma), and ovarian (microcystic stromal tumor) origin. In addition, several old and newly reported distinctive site-specific β-catenin-driven parenchymal neoplasms of uncertain histogenesis have been well characterized in recent studies, including solid-pseudopapillary neoplasm of the pancreas and its recently described ovarian counterpart, sclerosing hemangioma of lung and calcifying nested stromal-epithelial tumor of the liver. This review addresses the most relevant pathobiological and differential diagnostic aspects of β-catenin-altered neoplasms with emphasis on site-specific histologic and biological variations. In addition, the morphologic overlap and analogy as well as distinctness between these uncommon tumors will be presented and discussed. Furthermore, a note is made on association of some of these lesions with hereditary tumor syndromes, in particular with the familial adenomatous polyposis coli.