Which histologic findings are characteristic of vascular sarcomas of the pleura?

Updated: Dec 25, 2019
  • Author: Joseph F Tomashefski, Jr, MD; more...
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Histologically, EHE closely resembles either epithelioid or biphasic malignant mesothelioma. The tumor is composed of sheets, cords, and nests of large epithelioid cells with abundant amphophilic cytoplasm and round to oval nuclei with inconspicuous nucleoli. Nuclear pleomorphism is mild, and mitotic figures are inconspicuous. Tumor cells frequently contain bubbly cytoplasmic vacuoles in which erythrocytes are occasionally observed. Pseudoacini, microcysts, and spindle cells heighten the resemblance to malignant mesothelioma. Tumor cells are frequently embedded in a fibrohyaline or myxoid stroma. Histochemical stains are negative for mucin. [40, 41]

The histological features of angiosarcoma vary from well-differentiated slitlike vascular spaces to high-grade pleomorphic tumors bearing little resemblance to blood vessels. Epithelioid angiosarcomas are composed of moderately to extremely pleomorphic round to polygonal epithelioid cells with nuclei that contain large macronucleoli. Occasional intracytoplasmic lumina that contain erythrocytes may be observed.

Cells are typically arranged in sheets, islands, or cords. Focal areas of anastomosing vessels are usually present but may be lacking in small biopsy samples, which show only sheets of epithelioid cells. Within the sheetlike arrangement of epithelioid cells external laminal arrangement of cells into tubules recapitulates early vasculogenesis. Variable degrees of necrosis, hemorrhage, and numerous mitotic figures are present. [23]

Pathology of nonmesothelial cancers of the pleura. Pathology of nonmesothelial cancers of the pleura. Serosal angiosarcoma showing a pleomorphic spindle cell pattern with hemorrhage.
Pathology of nonmesothelial cancers of the pleura. Pathology of nonmesothelial cancers of the pleura. Serosal angiosarcoma showing primitive slit-like vascular channels.
Pathology of nonmesothelial cancers of the pleura. Pathology of nonmesothelial cancers of the pleura. Low magnification image of a pleural epithelioid hemangioendothelioma. Note the diffuse pleural thickening by a variably cellular and fibrous neoplasm. There is focal acute hemorrhage.
Pathology of nonmesothelial cancers of the pleura. Pathology of nonmesothelial cancers of the pleura. This histologic image reveals epithelioid hemangioendothelioma. Large epithelioid cells demonstrate prominent cytoplasmic vacuolization. Occasional vacuoles contain erythrocytes.

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