The genetics of vascular tumours: an update

CD26 Is Differentially Expressed throughout the Life Cycle of Infantile Hemangiomas and Characterizes the Proliferative Phase

Infantile hemangiomas (IHs) are benign vascular neoplasms of childhood (prevalence 5-10%) due to the abnormal proliferation of endothelial cells. IHs are characterized by a peculiar natural life cycle enclosing three phases: proliferative (≤12 months), involuting (≥13 months), and involuted (up to 4-7 years). The mechanisms underlying this neoplastic disease still remain uncovered. Twenty-seven IH tissue specimens (15 proliferative and 12 involuting) were subjected to hematoxylin and eosin staining and a panel of diagnostic markers by immunohistochemistry. WT1, nestin, CD133, and CD26 were also analyzed. Moreover, CD31pos/CD26pos proliferative hemangioma-derived endothelial cells (Hem-ECs) were freshly isolated, exposed to vildagliptin (a DPP-IV/CD26 inhibitor), and tested for cell survival and proliferation by MTT assay, FACS analysis, and Western blot assay. All IHs displayed positive CD31, GLUT1, WT1, and nestin immunostaining but were negative for D2-40. Increased endothelial cell proliferation in IH samples was documented by ki67 labeling. All endothelia of proliferative IHs were positive for CD26 (100%), while only 10 expressed CD133 (66.6%). Surprisingly, seven involuting IH samples (58.3%) exhibited coexisting proliferative and involuting aspects in the same hemangiomatous lesion. Importantly, proliferative areas were characterized by CD26 immunolabeling, at variance from involuting sites that were always CD26 negative. Finally, in vitro DPP-IV pharmacological inhibition by vildagliptin significantly reduced Hem-ECs proliferation through the modulation of ki67 and induced cell cycle arrest associated with the upregulation of p21 protein expression. Taken together, our findings suggest that CD26 might represent a reliable biomarker to detect proliferative sites and unveil non-regressive IHs after a 12-month life cycle.

Molecular Analysis of Renal/Adrenal Angiosarcomas Reveals High Frequency of Recurrent Genetic Alterations

Angiosarcomas of the kidney and adrenal gland are rare, highly aggressive vascular neoplasms. Their genomic profile has not been systematically studied to date. We report the clinicopathologic and molecular features of six angiosarcomas centered in the kidney/adrenal gland. All patients were male adults, ranging from 58 to 77 years of age. Tumor sizes ranged from 2.5 to 22.5 cm. Half of the cases demonstrated hot spot mutations in the KDR gene, while one-third demonstrated mutations in the PIK3CA gene; both of these gene alterations being previously described, preferentially in breast angiosarcomas. In addition, two cases each demonstrated BRIP1 gene amplification, CTNNB1 and ETV6 mutations, which have not been previously reported in angiosarcoma. Notably, molecular studies were critical in establishing the correct diagnoses in three cases: one was an epithelioid angiosarcoma originally misdiagnosed as metastatic adenocarcinoma to the adrenal gland, the second was a vasoformative angiosarcoma that mimicked hemangioma, and the third was a collision tumor between a high-grade angiosarcoma and a chromophobe renal cell carcinoma which was originally diagnosed as a sarcomatoid renal cell carcinoma. In summary, angiosarcomas of the kidney and adrenal gland have a high frequency of recurrent genetic alterations, some of them being shared with other angiosarcoma subtypes, while other appear to be novel. In particular, activating hot spot KDR and PIK3CA mutations represent potential therapeutic targets for these highly aggressive cancers.

Retroperitoneal infantile hemangioma: a case report and literature review

BACKGROUND

Retroperitoneal infantile hemangioma (RIH), a type of primary retroperitoneal tumors, are exceptionally rare in clinical practice. Infantile hemangiomas typically manifest on the skin's surface. RIHs are exceptionally rare and typically small. In adults, these tumors often manifest without specific clinical symptoms or detectable signs for a definitive diagnosis. This case report details a patient diagnosed with RIH. We recommend complete excision of the tumor after a comprehensive evaluation, followed by postoperative pathology, to achieve a conclusive diagnosis. We believe that managing critical retroperitoneal structures and vessels intraoperatively presents a significant challenge for all procedures involving primary retroperitoneal tumors. A 47-year-old male was diagnosed with gallstones and underwent surgery 3 months ago at other institution for unexplained nausea and vomiting. Follow-up imaging 2 months after surgery revealed a retroperitoneal mass below the left renal pole. Upon presentation to our hospital, the patient continued to experience intermittent nausea and vomiting, with no other significant symptoms or signs. Considering the patient's 8-year history of hypertension, a paraganglioma was initially suspected. We performed the laparoscopic mass resection after a detailed assessment. However, postoperative pathology revealed it a capillary hemangioma (old term)/infantile hemangioma.

CONCLUSION

RIHs are exceedingly rare benign tumor. The possibility of malignancy should be ruled out, and surgical resection is recommended following a thorough evaluation, with the diagnosis confirmed through pathological examination.

Postpolypectomy Bleeding Gone Wrong: Primary Colonic Epithelioid Angiosarcoma

Epithelioid angiosarcoma is an aggressive form of angiosarcoma, and primary colonic tumors are extremely rare. We present the case of a 60-year-old man who presented with what initially appeared to be postpolypectomy bleeding. After undergoing repeat endoscopy, he was found to have epithelioid angiosarcoma of the transverse colon, and imaging further confirmed that it was the primary tumor site. Our patient underwent segmental resection of his transverse colon. The patient's initial presentation as postpolypectomy bleeding and his continued cancer-free survival after a relatively limited surgery are unique features not previously seen.

Epithelioid Hemangioma of the Spine: A Case Series and Treatment Flow Chart-Experience from a Single Centre

Epithelioid hemangioma is recognized by the World Health Organization as a distinct benign neoplasm; however, it is characterized by locally aggressive and rarely metastasizing behavior. Epithelioid vascular tumors are rare bony vascular lesions with varying degrees of malignant potential that remain controversial because of their rarity, unusual morphological features, and unpredictable biological behavior. The application of new molecular tools, such as massive parallel sequencing technologies, have provided new diagnostic markers and an opportunity to further refine the classification of bone vascular neoplasms. Very few cases of EH of the spine have been reported in the literature; therefore, it is difficult to make evidence-based therapeutic decisions for these patients. We report herein our experience with eleven patients suffering from EH of the spine. The study population included three males and eight females treated in our center from 2016 to the present; the average age was 44.8 years (range 14-75 years). The surgical, clinical, and radiographic data were retrospectively analyzed. The mean follow-up was 34.8 months. All patients presented lytic vertebral body lesions, six of them with pathological fracture. The majority of patients (80%) presented myelo-radicular compression. All patients were surgically treated, and preoperative embolization was performed in all cases. In light of the literature review and the clinical experience of our center, we can consider EH a locally aggressive tumor that requires surgical treatment in case of symptoms. Here, we propose a treatment algorithm that could be useful in the management of patients with this rare disease.

Multifaceted roles of lymphatic and blood endothelial cells in the tumor microenvironment of hepatocellular carcinoma: A comprehensive review

The tumor microenvironment is a complex network of cells, extracellular matrix, and signaling molecules that plays a critical role in tumor progression and metastasis. Lymphatic and blood vessels are major routes for solid tumor metastasis and essential parts of tumor drainage conduits. However, recent studies have shown that lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) also play multifaceted roles in the tumor microenvironment beyond their structural functions, particularly in hepatocellular carcinoma (HCC). This comprehensive review summarizes the diverse roles played by LECs and BECs in HCC, including their involvement in angiogenesis, immune modulation, lymphangiogenesis, and metastasis. By providing a detailed account of the complex interplay between LECs, BECs, and tumor cells, this review aims to shed light on future research directions regarding the immune regulatory function of LECs and potential therapeutic targets for HCC.

Primary vascular tumors of bone: A comprehensive literature review on classification, diagnosis and treatment

Primary vascular tumors of bone are a heterogeneous group of neoplasms, ranging from benign hemangiomas to frankly malignant epithelioid hemangioendotheliomas and angiosarcomas. Over the years, their classification has been a matter of discussion, due to morphologic similarities and uncertainty regarding biologic behavior. Over the past decade, with the development of next-generation sequencing, there has been a significant improvement in the molecular characterization of these lesions. The integration of their morphologic, immunohistochemical and molecular features has led to a better stratification, with important prognostic and therapeutic implications. Nevertheless, primary vascular bone tumors still represent a challenge for medical oncologists. Given their rarity and heterogeneity, in the last few years, there has been no significant progress in medical treatment options, so further research is needed. Here we present a review of the current knowledge regarding primary vascular tumors of the bone, correlating clinicopathologic features with tumor behavior and therapeutic approaches.

The Pleural Origin of Retiform Hemangioendothelioma: An Unusual Origin of a Rare Diagnosis

Introduction

Vascular malignancies are categorized into benign hemangiomas, malignant angiosarcomas, and tumors of intermediate malignancy. Retiform hemangioendothelioma (RH) is one of the rare diagnoses belonging to the class of intermediate malignancies that was initially diagnosed.

Case Presentation

In this case report, we have reported a rare case of RH, a locally aggressive, vascular tumor of malignant potential presenting at an unusual site. The most observed locations of this soft tissue tumor are skin and subcutaneous tissues of extremities; however, this case of RH was observed in an unusual site called pleura, which is a rare occurrence related to this tumor. The presence of cell surface markers like CD31 and ERG of vascular and endothelial origin and the presence of hobnail appearance of endothelial channels on the biopsy profile supported the vascular origin of the tumor; the clinical features and imaging studies further confirmed the diagnosis of RH.

Conclusion

In this case report, a rare case of RH with an unusual site of origin was highlighted. RH is a vascular neoplasm; commonly observed sites of this vascular tumor were skin and subcutaneous tissue of the extremities; however, in this case, the site was unusually different, which was the pleura of the left lung.

A cutaneous epithelioid vascular tumor harboring a TPM3::ALK fusion

Substantial progress has been made in understanding the molecular pathways associated with vascular tumors over the last two decades. In addition to mutations and copy number aberrations, fusions have emerged as significant contributors to the pathogenesis of a notable subset of vascular tumors. In this report, we present a case of an unusual intradermal vascular tumor with epithelioid cytomorphology. Immunohistochemistry revealed diffuse positivity for CD31, ERG and Factor VIII, supporting its endothelial lineage. RNA sequencing (ArcherFusion Plex) revealed the presence of an in-frame fusion between the genes TPM3 Exon 8 and ALK Exon 20. Immunohistochemistry confirmed ALK expression by the endothelial cells. To our knowledge, this is the first documented case of a vascular tumor harboring an ALK fusion. It may fall within the spectrum of epithelioid hemangiomas; nevertheless, we cannot definitively exclude the possibility of it being a distinct and potentially unique benign entity on its own.

Current Model Systems for Investigating Epithelioid Haemangioendothelioma

Epithelioid haemangioendothelioma (EHE) is a rare sarcoma of the vascular endothelium with an unpredictable disease course. EHE tumours can remain indolent for long period of time but may suddenly evolve into an aggressive disease with widespread metastases and a poor prognosis. Two mutually exclusive chromosomal translocations define EHE tumours, each involving one of the transcription co-factors TAZ and YAP. The TAZ-CAMTA1 fusion protein results from a t(1;3) translocation and is present in 90% of EHE tumours. The remaining 10% of EHE cases harbour a t(X;11) translocation, resulting in the YAP1-TFE3 (YT) fusion protein. Until recently, the lack of representative EHE models made it challenging to study the mechanisms by which these fusion proteins promote tumorigenesis. Here, we describe and compare the recently developed experimental approaches that are currently available for studying this cancer. After summarising the key findings obtained with each experimental approach, we discuss the advantages and limitations of these different model systems. Our survey of the current literature shows how each experimental approach can be utilised in different ways to improve our understanding of EHE initiation and progression. Ultimately, this should lead to better treatment options for patients.

Benign and low-grade superficial endothelial cell neoplasms in the molecular era

Vascular tumors are the most common mesenchymal neoplasms of the skin and subcutis, and they encompass a heterogeneous group with diverse clinical, histological, and molecular features, as well as biological behavior. Over the past two decades, molecular studies have enabled the identification of pathogenic recurrent genetic alterations that can be used as additional data points to support the correct classification of these lesions. The purpose of this review is to summarize the available data related to superficially located benign and low-grade vascular neoplasms and to highlight recent molecular advances with the role of surrogate immunohistochemistry to target pathogenic proteins as diagnostic biomarkers.

Inflammatory Lobular Hemangioma (T-cell Rich Angiomatoid Polypoid Pseudolymphoma) - Assessment of FOS/FOSB and Lymphoid Markers and Comparison with Epithelioid Hemangioma

BACKGROUND

T-cell rich angiomatoid polypoid pseudolymphoma (TRAPP) and inflammatory lobular hemangioma (ILH) encompass a spectrum of cutaneous vascular lesions in which a prominent lymphoplasmacytic component may impart a pattern highly reminiscent of low-grade cutaneous lymphoma (pseudolymphoma). Epithelioid hemangioma, including its most common variant angiolymphoid hyperplasia with eosinophilia (ALHE), is a distinct entity associated with FOS and/or FOSB expression detected by immunohistochemistry (IHC). These entities can show significant morphological overlap.

METHODS

We performed IHC for FOSB, FOS and lymphoid markers in a series of TRAPP/ILH and ALHE.

RESULTS

We identified 13 cases of ILH/TRAPP, which showed a predominance in CD8+ T cells (CD8>CD4: 11/13) while FOSB and FOS were expressed in 36% (4/11) and 27% (3/11) of cases, respectively. ALHE (n=9) showed a predominance in CD4+T cell (67%) with FOSB and FOS co-expression in 78% (7/9) of the cases.

CONCLUSION

We demonstrated, based on FOS and/or FOSB immunohistochemical expression, that there is a possible link between ILH/TRAPP and epithelioid hemangioma / ALHE. The use of FOS and FOSB IHC in the routine diagnostic setting of cutaneous vascular lesions will help to redefine cases of ILH/TRAPP as a subset of these may represent inflammatory variants of epithelioid hemangioma.

A Rare Case of Primary Epithelioid Hemangioma of Bone with WWTR1::FOSB Fusion: A Benign Lesion with the Potential to Mimic Malignancy

Epithelioid hemangioma of bone is a rare benign, locally aggressive vascular tumor that can be particularly challenging to diagnose given its frequent multifocality, non-specific imaging findings, and wide range of morphologic appearances. Additionally, some epithelioid hemangiomas demonstrate atypical histologic features including increased cellularity, necrosis, and moderate cytologic atypia - characteristics that may raise concern for malignancy. Molecular studies can serve as a powerful, objective tool in the differential diagnosis of diagnostically challenging epithelioid vascular tumors. Importantly, FOS and FOSB gene rearrangements have been identified as the genetic hallmarks of osseous epithelioid hemangioma, present in greater than 70% of cases. FOSB-fusion-positive epithelioid hemangioma, in particular, may display atypical histologic features. While ZFP36 is the typical FOSB fusion partner in epithelioid hemangioma, we herein present a case of epithelioid hemangioma of bone with a rare WWTR1::FOSB fusion. This case demonstrates the diagnostic challenges associated with epithelioid hemangioma, especially in the setting of FOSB gene rearrangements, and the importance of genomic studies in the work up of these vascular tumors.

Immunohistochemistry for FOSB and FOS is a Useful Ancillary Tool in the Diagnosis of Epithelioid Hemangioma but There are Pitfalls in Interpretation Including Expression in Other Vascular Lesions

Introduction: Epithelioid hemangioma is a benign vascular neoplasm associated with FOS and/or FOSB protein overexpression detected by immunohistochemistry (IHC). Methods: The aim of our study was to determine the co-expression or independent IHC expression of FOS and FOSB in a cohort of epithelioid hemangiomas. We also included two cohorts of other vascular lesions: papillary endothelial hyperplasia and lobular capillary hemangioma / pyogenic granuloma. Results: We identified 50 cases of epithelioid hemangioma, 84% of which were cutaneous and the remaining involved other anatomic locations. Over two thirds of all cases expressed FOSB (68%; 34/50) while FOS immunoreactivity was identified in 46% of all cases. Co-expression of FOSB and FOS occurred in 37% of cases while 76% of all cases stained for at least one of the antibodies. Fifty-eight percent (n = 14/24) and 33% (8/24) of all cases of papillary endothelial hyperplasia expressed FOS and FOSB, respectively. Thirty-two per cent of lobular capillary hemangiomas (n = 8/25) were positive for either FOS or FOSB. Conclusion: In summary, we present the largest cohort of epithelioid hemangiomas assessed with both FOS and FOSB and demonstrated that the use of both antibodies increases the detection rate of these proliferations by 10%. Nonetheless, the use of thresholds may not be appropriate, as only a subset of lesional endothelial cells label with FOS/FOSB. Over half of all cases of papillary endothelial hyperplasia and a third of lobular capillary hemangiomas also displayed immunoreactivity with FOS and/or FOSB.