Pulmonary Pathology Online
Ten things to remember about Pathology of Epithelioid Hemangioendothelioma of the Lung
Epithelioid hemangioendothelioma is a low-grade malignant vascular
tumour that was previously considered an intermediate vascular
tumour (between hemangioma and conventional angiosarcoma), but was
reclassified as a low-grade angiosarcoma in the 2002 WHO
(2) Pulmonary epithelioid hemangioendothelioma (PEH) is the current term for a rare neoplasm originally described by Dail and Liebow in 1975 as intravascular sclerosing bronchioalveolar tumour of the lung.
(3) Development of immunohistochemical techniques confirmed its endothelial lineage, and Wiess et al. subsequently suggested the current name, "epithelioid hemangioendothelioma".
(4) Pulmonary epithelioid hemangioendothelioma, typically manifests as multiple bilateral lung nodules that are usually discovered incidentally in young or middle-aged women, although cases in children and the elderly have also been reported.
(5) Symptomatic patients , presence of cough, hemoptysis, chest pain, multiple unilateral nodules, pleural effusion, metastases to more than one site and lymph node metastases are the factors associated with a poor prognosis.
(6) Most commonly, PEH presents as bilateral or unilateral multiple pulmonary nodules with clear boundaries, diameters of 0.3–2 cm, pale gray or brown coloration and these can invade the pleura and cause pleural effusion or nodular thickening.
(7) Distinctive histological features are epithelioid tumour cells with nests, cords and strands embedded in a sclerosing, hyaline matrix with alveolar, bronchiolar and vascular extension.
(8) Areas of necrosis and ossification may be present and the mitotic index is usually below one mitosis in 10 HPF.
(9) Immunohistochemical examination of the tumour shows positivity for CD31, CD34 and most of the tumours are positive for factor VIII, and negative for pancytokeratin and calretinin.
(10) Due to the fact that PEH is rare, clinically, it is easily confused with a variety of benign and malignant lung diseases.
The differential diagnosis of PEH includes chronic granulomatous disease, amyloid nodules, hamartoma, primary or metastatic lung cancer, malignant mesothelioma and angiosarcoma.
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