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Romeu Duarte Mesquita [1] and Marta Sousa [1] and Carmen Trinidad [2] and Eugénia Pinto [3] and Iosu Antón Badiola [4]
Academic Editor: Suayib Yalcin
1, Department of Radiology, Centro Hospitalar de Entre o Douro e Vouga, Santa Maria da Feira, Portugal, min-saude.pt
2, Department of Radiology, Hospital Povisa, Vigo, Spain, povisa.es
3, Department of Pathology, Centro Hospitalar de Lisboa Central, Lisboa, Portugal, min-saude.pt
4, Department of Pathology, Hospital Povisa, Vigo, Spain, povisa.es
Received Apr 10, 2017; Accepted Jul 4, 2017
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
Pulmonary epithelioid hemangioendothelioma (PEH) is a rare neoplasm of vascular origin. It is a low-to-intermediate grade malignant tumor, of borderline malignancy and a clinical course usually between hemangioma and angiosarcoma. Unfortunately, there is no clear definition of malignant PEH. The term “epithelioid hemangioendothelioma” was first introduced by Weiss et al. as a soft tissue vascular tumor of borderline malignancy [1].
However, the lesion was originally described in 1975 by Dail et al. as an “intravascular bronchoalveolar tumor,” initially believed to be an aggressive form of the bronchoalveolar cell carcinoma [2].
Epithelioid hemangioendothelioma (EH) is classified as a vascular tumor because the neoplastic cells have characteristics in common with normal, nonneoplastic endothelial cells [3]. EH can behave in a locally aggressive fashion, with metastases being rare [4].
Corrin et al., using immunohistochemical techniques, demonstrated the presence of malignant cells deriving from a lineage capable of differentiation along endothelial lines [5]. Subsequently, Weldon-Linne et al., using electron microscopy, confirmed these results and revealed diffuse cytoplasmic staining of the tumor cells with a factor VIII-related antigen [6].
Histologic characteristics of EH include epithelioid cells with abundant eosinophilic cytoplasm in a fibromyxoid stroma, some of them with intracytoplasmic vacuoles, having a signet ring-like appearance. These features can, however, be also found in primary adenocarcinoma, mesothelioma, and large-cell lymphoma, so immunohistochemical analyses, especially those for the endothelial markers, are a mainstay [7–10].
The 2015 WHO Classification of Tumors of the Lung, Pleura, Thymus and Heart [11] recently published, with numerous important changes from the 2004 WHO classification, has a significant change involving recognition of usefulness of