Epithelioid Hemangioma of Bone: A Potentially Metastasizing Tumor?

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.

Fusion transcriptome profiling defines the monoclonal origin of multifocal epithelioid haemangioma of bone

AIMS

Epithelioid haemangioma (EH) of bone remains a highly controversial entity. Indeed, the WHO classifies EHs of soft tissues as benign tumours, whereas bone EHs are considered intermediate-locally aggressive tumours due to common multifocal presentation and local destructive growth. To gain insights into the clinical behaviour and biology of EH of bone we retrospectively analysed 42 patients treated in a single institution from 1978 to 2021.

METHODS AND RESULTS

Multifocal presentation was detected in 17 of 42 patients (40%) primarily as synchronous lesions. Patients were treated with curettage (57%), resection (29%) or biopsy, followed by radiotherapy or embolisation (14%). Follow-up (minimum 24 months) was available for 38 patients, with only five local recurrences (13%) and no death of disease. To clarify whether the synchronous bone lesions in multifocal EH represent multicentric disease or clonal dissemination, four cases were profiled by RNA-sequencing. Separate lesions from the same patient, which showed a similar transcriptional profile, expressed the same fusion transcript (involving FOS or FOSB) with identical gene breakpoints.

CONCLUSIONS

These results indicate that, in EH of bone, multifocal lesions are clonally related and therefore represent the spread of a same neoplastic clone rather than simultaneous independent tumours. This finding is in apparent contradiction with the benign clinical course of the disease, and suggests that tumour dissemination in bone EH probably reflects a phenomenon of passive spreading, with tumour cells colonising distal sites while maintaining their benign biological nature.

Nonvascularized Double Metatarsal Transfer After Excision of Epithelioid Hemangioma of Hand: A Case Report

CASE

Epithelioid hemangioma (EH) is an uncommon, benign, locally aggressive neoplasm, and it may present as multifocal lytic lesions with soft tissue involvement in the hand. We report the midterm follow-up of a patient with recurrent EH of the hand that was reconstructed successfully, with a nonvascularized double metatarsal transfer, after tumor excision. To the best of the authors' knowledge, this is the first case report where a nonvascularized double metatarsal transfer has been used successfully after tumor resection.

CONCLUSION

Osteoarticular replacement with matched metatarsal transfer after en bloc resection may be used successfully for reconstruction, after the resection of EH involving the metacarpal.

Epithelioid Haemangioma of Bone: A Case Series and Comprehensive Literature Review Reappraising the Diagnostic Classification of All Epithelioid Vascular Neoplasms of Bone

Epithelioid vascular neoplasms of the bone are classified by the World Health Organization (WHO) into only two tiers: low-grade epithelioid hemangioma (EH) and a more malignant category including both epithelioid hemangioendothelioma and epithelioid angiosarcoma. The World Health Organization defines bone EH as a locally aggressive neoplasm with no connotation of benign or intermediate malignancy. We reviewed three cases of EH in our lab archives with the perspective of appraising their histomorphological approach toward diagnosis. Patients were in the age range of 15-25 years. The site of the neoplasms ranged from the carpal bones to the metatarsal bones. Histomorphological examination of the lesions showed a nodular growth pattern of a vascular neoplasm without demonstrable vessel origin. The vasoformative area increased from the center to the periphery, with prominent epithelioid morphology of the endothelial cells at the periphery and an associated inflammatory infiltrate comprising eosinophils, lymphocytes, and plasma cells. The growth pattern was diffuse, with extension into the deeper dermis of overlying skin.

Epithelioid hemangioma of bone harboring FOS and FOSB gene rearrangements: A clinicopathologic and molecular study

The diagnosis of epithelioid hemangioma (EH) remains challenging due to its rarity, worrisome histologic features, and locally aggressive clinical and radiographic presentation. Especially in the bone, EH can be misdiagnosed as a malignant vascular neoplasm due its lytic, often destructive or multifocal growth, as well as atypical morphology. The discovery of recurrent FOS and FOSB gene fusions in the pathogenesis of most EH has strengthened its stand-alone classification, distinct from other malignant epithelioid vascular lesions, such as epithelioid hemangioendothelioma or angiosarcoma. In this study we investigate a group of molecularly confirmed skeletal EH by the presence of FOS or FOSB gene rearrangements to better define its clinical and pathologic characteristics within a homogenous molecular subset. The cohort included 38 patients (25 males, 13 females), with a mean age at diagnosis of 38 years (range, 4-75). Regional, multifocal presentation was noted in 10 cases. Only six cases were correctly recognized as EH by the referring institutions, while most were misdiagnosed as other vascular tumors. Of the 17 patients with follow-up data available, five patients (29%) developed local recurrence after marginal en bloc excision (n = 3) or curettage (n = 2). Local recurrence-free survival rates were 84% at 3 years and 38% at 5 years. No metastasis or disease-related death was identified. Imaging studies exhibited no specific features, showing cortical bone destruction and soft-tissue extension in 14 (38%) cases. FOS gene rearrangements were detected in 28 (74%) of cases, while FOSB rearrangements in 10 (26%) cases. Our results highlight the significant challenges encountered in establishing a correct diagnosis exclusive of the molecular testing, mainly due to its overlap to other malignant epithelioid vascular tumors. Skeletal EH emerges as a genetically defined locally aggressive vascular neoplasm, with a high rate of local recurrence, but lacking the propensity for distant spread.

Epithelioid Vascular Tumors: A Review

Vascular tumors are a diagnostically challenging area. This is particularly true in the case of epithelioid vascular tumors. Not only is the distinction between different epithelioid vascular tumors challenging, but also the differential diagnosis may be substantially expanded by the inclusion of melanoma, carcinomas, and other epithelioid soft tissue tumors. Recently developed immunohistochemical markers and more comprehensive genetic characterizations continue to advance our understanding of epithelioid vascular tumors. The present paper briefly reviews and updates basic concepts with regard to the following epithelioid vascular tumors: epithelioid hemangioma, epithelioid angiomatous nodule, pseudomyogenic hemangioendothelioma, composite hemangioendothelioma, epithelioid hemangioendothelioma, and epithelioid angiosarcoma.

Epithelioid hemangioma of bone: A unique case with multifocal metachronous bone lesions

Epithelioid hemangioma of bone is a rare vascular neoplasm with a ubiquitous distribution. To date, up to 25% epithelioid hemangioma of bone presents synchronous bone lesions. We report a unique case of epithelioid hemangioma with multifocal metachronous bone lesions without any fatal outcome observed after a long period. Importantly, a strong nuclear expression of FOSB antibody was detected by immunohistochemical analysis. In this case, the pathologic and radiologic findings are also described. We suggest that epithelioid hemangioma can present multifocal metachronous bone lesions without producing a fatal outcome.

Epithelioid hemangioma of the scapula treated with chemoembolization and microwave ablation: Α case report

Bone epithelioid hemangiomas are classified within benign vascular tumours but are commonly misdiagnosed as low-grade angiosarcomas or epithelioid hemangioendotheliomas. Current therapeutic interventions include various treatment options but local recurrence or distal lymph node involvement has been reported. We report a rare case of scapular epithelioid hemangioma that was initially treated using a combination of chemoembolization and microwave ablation. This combination has not been previously reported in the literature regarding the management of this tumour. A year after the first course of treatment, the tumour size has been reduced more than 70% and the patient has remarkable clinical improvement. Results reported in this case study demonstrated that combination of chemoembolization and microwave ablation is a feasible, safe and effective technique in the treatment of bone epithelioid hemangiomas. Even if the tumour is still present afterwards, a substantially smaller surgical excision will be needed.

Epithelioid hemangioma of bone: radiologic and magnetic resonance imaging characteristics with histopathological correlation

BACKGROUND

Epithelioid hemangioma is a rare vascular tumor that can occur in soft tissues or bone. The tumor is part of a spectrum of vascular tumors that also includes epithelioid hemangioendothelioma and angiosarcoma. When involving the bone, the tumor usually involves the metaphysis or diaphysis of the long tubular bones and most commonly occurs in adults. It has been rarely reported in pediatric patients, and in these reported patients, the tumor primarily involves the epiphysis.

OBJECTIVE

To review three cases of epithelioid hemangioma of bone occurring in pediatric patients involving the epiphysis and to explore the imaging features of this tumor.

MATERIALS AND METHODS

Retrospectively review three cases of epithelioid hemangioma occurring in skeletally immature patients.

RESULTS

These tumors primarily involved the epiphyses or epiphyseal equivalent bones. One lesion was centered in the metaphysis but extended to the epiphysis. These are three cases presenting in an unusual location and at an unusual age.

CONCLUSION

Epithelioid hemangioma, though rare, can occur in pediatric patients and appears to involve the epiphyses in these patients. This is in contrast to the usual age and location reported. Epithelioid hemangioma may be considered for an epiphyseal lesion in a skeletally immature patient.

The Disappearing Phalanx: A Case Report of a Vascular Tumor of the Toe

We report a unique case of an epithelioid hemangioma of the third middle phalanx in which the lesion replaced the phalanx, became symptomatic, and then required resection, bone grafting, and joint arthroplasty. To the best of our knowledge, this is the first report of an epithelioid hemangioma in the toe that was treated using this approach.

Epithelioid hemangioma of bone: a report of two special cases and a literature review

Intraosseous epithelioid hemangioma (EH) is a rare intermediate vascular neoplasm, characterized by locally aggressive and rarely metastasizing behavior. Occasionally, EH of bone can behave strangely and may simulate malignant neoplasm. Here, we report two cases of EH of bone. Of interest was the fact that the computed tomography and magnetic resonance images from one case showed an osteolytic lesion in the right scapula, with multiple swollen lymph nodes in the right supraclavicular and axillary areas. Another patient exhibited a local recurrence in the cervical vertebrae. The initial radiological diagnosis of both cases was metastatic tumor. EH should be included in the differential diagnosis of a radiographic osteolytic lesion with an aggressive appearance. Also, we reviewed the literature that reported EH of bone and summarized their radiological appearances. The cases of EH of bone that exhibited involvement of regional or draining lymph nodes were also summarized.

The debate is still open; benign or malignant: a case report of a multifocal epithelioid haemangioma of fibula

In this case, we report an epithelioid haemangioma (EH) of the fibula with ill-defined multifocal lesions and a resultant pathologic fracture. Based on radiographic appearance, these lesions were initially thought to represent a malignant process, such as primary malignant bone tumour, metastases or multiple myeloma. Osseous EHs are rare. Although they can present as multifocal lesions, the majority of bony EHs are solitary and arise in the diaphysis or metaphysis of long tubular bones, with a predilection for the lower extremity. Non-specific radiological findings, debatable cytological appearance and unpredictable clinical growth patterns commonly cause misdiagnosis of malignancy. To the best of our knowledge, a case of EH with multiple growing lesions of the fibula has not yet been reported in the literature.

Advances in the clinicopathological and molecular classification of cutaneous mesenchymal neoplasms

In recent years, there have been several important refinements in the classification of cutaneous mesenchymal neoplasms, including the description of new tumour types, along with the identification of novel and recurrent molecular genetic findings. In addition to providing new insights into tumour biology, many of these advances have had significant clinical consequences with regard to diagnostics, management, and prognostication. Newly described entities include pseudomyogenic haemangioendothelioma, haemosiderotic fibrolipomatous tumour, and fibroblastic connective tissue naevus, which are reviewed in the context of the principal differential diagnoses and significant clinical implications. Genetic characterization of several soft tissue tumour types that occur in the skin has resulted in the identification of diagnostically useful markers: ALK gene rearrangement with corresponding ALK protein expression by immunohistochemistry in epithelioid fibrous histiocytoma; the WWTR1-CAMTA1 fusion gene with CAMTA1 protein expression in epithelioid haemangioendothelioma; MYC amplification and overexpression in radiation-associated angiosarcoma; and EWSR1 gene rearrangement in cutaneous myoepithelial tumours. Finally, the classification of intradermal smooth muscle tumours and unclassified/pleomorphic dermal sarcoma has been refined, resulting in both improved classification and improved prognostication. Many of the tumour types listed above are encountered not only by specialist dermatopathologists, but also by practising general surgical pathologists, and this review should therefore provide a widely applicable update on the histological and molecular classification of cutaneous mesenchymal neoplasms, along with the appropriate use of ancillary diagnostic tests, in particular immunohistochemistry, in the evaluation of such lesions and their histological mimics.

Frequent FOS Gene Rearrangements in Epithelioid Hemangioma: A Molecular Study of 58 Cases With Morphologic Reappraisal

Epithelioid hemangioma (EH) is a unique benign vasoformative tumor composed of epithelioid endothelial cells. Although a small subset of EHs with atypical features harbor ZFP36-FOSB fusions, no additional genetic abnormalities have been found to date in the remaining cases. On the basis of a novel FOS-LMNA gene fusion identified by RNA sequencing in an index case of a skeletal EH with typical morphology, we sought to investigate the prevalence of FOS rearrangement in a large cohort of EHs. Thus 57 additional EH cases lacking FOSB rearrangements were studied for FOS gene abnormalities by fluorescence in situ hybridization, and results were correlated with morphologic appearance and clinical presentation. The EHs were subclassified as typical (n=25), cellular (n=21), and angiolymphoid hyperplasia with eosinophilia (ALHE) (n=12) variants. The ALHE was defined as an EH with a vascular "blow-out" pattern associated with a variable degree of inflammation. There were 17 (29%) cases bearing FOS gene rearrangements among 58 cases tested, including 12 male and 5 female patients, with a mean age of 42 years. Most FOS-rearranged EHs occurred in the bone (10) and soft tissue (6), whereas only 1 case was cutaneous. The predominant anatomic site was the extremity (12), followed by trunk (3), head and neck (1), and penis (1). The incidence of FOS rearrangement was significantly higher in bone (59%, P=0.006) and lower in head and neck (5%, P=0.009). Twelve of the FOS-rearranged cases were cellular EH (P=0.001) associated with moderate mitotic activity (2 to 5/10 HPF) and milder inflammatory background. All 12 ALHE cases lacked FOS gene abnormalities, suggesting different pathogenesis. In conclusion, FOS rearrangement was present in a third of EHs across different locations and histologic variants; however, it was more prevalent in cellular EH and intraosseous lesions, compared with those in skin, soft tissue, and head and neck. This genetic abnormality can be useful in challenging cases, to distinguish cellular EHs from malignant epithelioid vascular tumors. These results also suggest that dysregulation of the FOS family of transcription factors through chromosomal translocation is as a key event in the tumorigenesis of EH except for the ALHE variant.

Vascular tumors of bone

Vascular tumors of the bone represent a variety of neoplasms, ranging from benign hemangiomas and epithelioid hemangiomas to intermediate grade hemangioendotheliomas to frankly malignant angiosarcomas. Over the years, there has been considerable debate concerning the aggressivity, nomenclature, and mere existence of various nosologic entities, due to morphologic similarities and uncertainty regarding biologic behavior. Such debate has led to confusion among pathologists and clinicians, thus diminishing the prognostic implications in the diagnosis of these lesions. Here we review the current knowledge concerning the primary vascular neoplasms of the bone and correlate clinicopathologic features with tumor behavior.

Vascular bone tumors: a proposal of a classification based on clinicopathological, radiographic and genetic features

The classification of vascular bone tumors remains challenging, with considerable morphological overlap spanning across benign to malignant categories. The vast majority of both benign and malignant vascular tumors are readily diagnosed based on their characteristic histological features, such as the formation of vascular spaces and the expression of endothelial markers. However, some vascular tumors have atypical histological features, such as a solid growth pattern, epithelioid change, or spindle cell morphology, which complicates their diagnosis. Pathologically, these tumors are remarkably similar, which makes differentiating them from each other very difficult. For this rare subset of vascular bone tumors, there remains considerable controversy with regard to the terminology and the classification that should be used. Moreover, one of the most confusing issues related to vascular bone tumors is the myriad of names that are used to describe them. Because the clinical behavior and, consequently, treatment and prognosis of vascular bone tumors can vary significantly, it is important to effectively and accurately distinguish them from each other. Upon review of the nomenclature and the characteristic clinicopathological, radiographic and genetic features of vascular bone tumors, we propose a classification scheme that includes hemangioma, hemangioendothelioma, angiosarcoma, and their epithelioid variants.

Epithelioid hemangioma of bone and soft tissue: a reappraisal of a controversial entity

BACKGROUND

The controversy surrounding diagnosis of an epithelioid hemangioma (EH), particularly when arising in skeletal locations, stems not only from its overlapping features with other malignant vascular neoplasms, but also from its somewhat aggressive clinical characteristics, including multifocal presentation and occasional lymph node involvement. Specifically, the distinction from epithelioid hemangioendothelioma (EHE) has been controversial. The recurrent t(1;3)(p36;q25) chromosomal translocation, resulting in WWTR1-CAMTA1 fusion, recently identified in EHE of various anatomic sites, but not in EH or other epithelioid vascular neoplasms, suggests distinct pathogeneses.

QUESTION/PURPOSES

We investigated the clinicopathologic and radiologic characteristics of bone and soft tissue EHs in patients treated at our institution with available tissue for molecular testing.

PATIENTS AND METHODS

Seventeen patients were selected after confirming the pathologic diagnosis and fluorescence in situ hybridization analysis for the WWTR1 and/or CAMTA1 rearrangements. Four patients had multifocal presentation. Most patients with EH of bone were treated by intralesional curettage. None of the patients died of disease and only four patients had a local recurrence.

RESULTS

Our results, using molecular testing to support the pathologic diagnosis of EH, reinforce prior data that EH is a benign lesion characterized by an indolent clinical course with an occasional multifocal presentation and rare metastatic potential to locoregional lymph nodes.

CONCLUSION

These findings highlight the importance of distinguishing EH from other malignant epithelioid vascular tumors as a result of differences in their management and clinical outcome.

LEVEL OF EVIDENCE

Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Epithelioid hemangioma of the distal humerus with pathologic fracture

Epithelioid hemangioma is a rare tumor that can have bone involvement. Its clinically and radiographically aggressive appearance mimics a malignant neoplasm. Although epitheliod hemangioma has been described as having an aggressive appearance on magnetic resonance imaging (MRI) and plain radiographs, this is the first reported case of pathologic fracture associated with this lesion to our knowledge. This article describes a case of epithelioid hemangioma involving the distal humerus, which initially presented with progressive pain and fracture of the lateral condyle. The aggressive appearance on plain radiographs and MRI suggested a malignant bone tumor. This preliminary diagnosis was confirmed due to the presence of local lymph node spread on positron emission tomography/computed tomography. After a core needle biopsy revealed nondiagnostic tissue, rather than performing a wide resection based on a presumptive malignant diagnosis, we followed the standard diagnostic algorithm and performed an open biopsy with temporary internal stabilization. The tissue sample was adequate and revealed a diagnosis of epithelioid hemangioma. Based on this finding, we were able to proceed with surgical management, including curettage of the lesion, placement of a bone graft, and internal fixation, rather than a wide resection with elbow joint replacement. This article emphasizes the need for careful adherence to the diagnostic algorithm for musculoskeletal tumors. In doing so, a definitive diagnosis was reached, and our patient was able to resume his occupation as a laborer without the restrictions that would have accompanied elbow arthroplasty.

[A case of epithelioid hemangioma of the spine]

Epithelioid hemangioma is a rare and benign vascular tumor, most often occurring in the skin. Numerous other localizations, including bones, have been reported. The overall favorable clinical outcome of cutaneous epithelioid hemangioma is now well documented, but it still remains debated in osseous localization, as local recurrences and metastases have been described. We report a case of epithelioid hemangioma of the spine occurring in a 25-year-old male, and discuss main differential diagnoses. Recent studies tend to demonstrate that osseous epithelioid hemangioma, as cutaneous epithelioid hemangioma, should be considered as a benign tumor. Histologically, epithelioid hemangioma consists of a vascular proliferation with diffuse or lobular pattern and features vascular spaces lined by epitheliod endothelial cells with numerous lymphocytes and eosinophils. The main differential diagnosis is represented by epithelioid hemangioendothelioma, the surgical treatment of which must be more aggressive. Precise histological diagnosis is essential for accurate clinical management and to avoid overtreatment.

Epithelioid hemangioma of bone revisited: a study of 50 cases

The clinical and pathologic features of 50 epithelioid hemangiomas of bone are analyzed. There were 29 males and 21 females who ranged in age from 10 to 75 (mean 35) years. The tumors arose in long tubular bones (40%), short tubular bones of the distal lower extremity (18%), flat bones (18%), vertebrae (16%), and small bones of the hands (8%). Nine patients (18%) had involvement of more than 1 bone. Radiographically, the lesions were lucent and well marginated. Microscopically, the neoplasms had a lobular architecture and were composed of epithelioid endothelial cells that formed obvious vascular lumina or grew in solid sheets. No hyalinized or solid appearing extracellular myxoid matrix was present. Thirty-five patients were treated with curettage, 13 patients had a local resection and 2 patients only had a biopsy. One patient had local lymph node involvement. Three patients were treated with surgery and radiation therapy. Follow-up information revealed that 4 patients experienced a local recurrence; and 1 patient developed limited involvement of a regional lymph node. Epithelioid hemangioma of bone is a benign lesion that may be multifocal and affect separate tissue and is successfully treated with curettage or marginal en bloc excision.