Composite hemangioendotheliomas are locally aggressive and rarely metastasizing vascular tumors consisting of different and histologically distinct elements.
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Epidemiology
Composite hemangioendotheliomas are very rare and mostly seen in adults. Women are slightly more commonly affected 1,2.
Diagnosis
The diagnosis of composite hemangioendothelioma is established histologically 1.
Diagnostic criteria
The diagnostic criterion according to the WHO classification of soft tissue and bone tumors (5th edition)1:
- presence of two or more morphologically distinct tumor components (usually similar to hemangioendothelioma and epithelioid hemangioendothelioma)
- at least two additional endothelial tumor elements in cases originating from pre-existing vascular or lymphatic malformations
- conventional angiosarcoma needs to be excluded clinically and morphologically if there are foci resembling high-grade angiosarcoma
Clinical presentation
The typical complaint is a lump with a reddish-to-purple appearance which has been there for a long time 1.
Associations
Composite hemangioendotheliomas are seen in patients with lymphedema 1.
Pathology
Composite hemangioendotheliomas are formed by at least two histologically different vascular tumor components. These parts often resemble retiform or epithelioid hemangioendotheliomas 1.
Etiology
Chronic lymphedema and irradiation are thought to have a role in the etiology 1.
Subtypes
Neuroendocrine composite hemangioendothelioma is the only subtype.
Location
Composite hemangioendotheliomas most frequently affect the skin and subcutaneous tissues of the distal extremities or the head and neck area but have been also found in other sites 1,2.
Macroscopic appearance
Macroscopically composite hemangioendotheliomas are nodular infiltrative ill-defined lesions 1,2.
Microscopic appearance
The microscopic spectrum of composite hemangioendotheliomas consists of a composition of different morphological vascular components and areas including the following 1,2:
- epithelioid hemangioendothelioma
- retiform hemangioendothelioma
- spindle-cell hemangioma
- angiosarcoma-like
- lymphangioma
- angiomatosis
- cavernous hemangioma
Neuroendocrine composite hemangioendotheliomas are typically composed of epithelioid and retiform hemangioendothelioma-like parts with a nest-like appearance 1.
Immunophenotype
Immunohistochemistry stains usually express CD31, ERG and FLI1 and can be positive CD34 and D2-40 1.
Genetics
Fusions of the PTBP1-MAML2 and EPC1-PCH2 genes have been observed in neuroendocrine composite hemangioendotheliomas 1.
Radiographic features
MRI
Composite hemangioendotheliomas are vascular lesions with a lobulated and heterogeneous appearance 2-4.
Signal characteristics
- T1: low to intermediate signal intensity
- T2: high signal intensity
- T2FS/STIR: high signal
- T1 C+ (Gd): avid enhancement
Radiology report
The radiological report should include a description of the following features:
- form, location and size
- tumor margins
- relation to the muscular fascia
- relationship to bones, tendons and joints
- relationship to local nerves and vessels
Treatment and prognosis
Due to the rarity of the tumors, there is no clear management strategy as yet. Treatment usually consists of surgical excision. Local recurrence is common and can happen multiple times. Lymph node metastases can occur. Distant metastases are seen in neuroendocrine composite hemangioendotheliomas, which are more aggressive 1.
History and etymology
Composite hemangioendotheliomas were first described by an international group around the South African pathologist Simon J. Nayler in 2000 5.
Differential diagnosis
The differential diagnosis of composite hemangioendotheliomas consists of the following:
- retiform hemangioendothelioma
- epithelioid hemangioendothelioma
- Dabska tumor
- Kaposiform hemangioendothelioma
- Kaposi sarcoma
- angiosarcoma
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