Primary pleural angiosarcoma as a mimicker of mesothelioma: a case report

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1059343251633446 webciteAngiosarcoma is an uncommon malignant tumor of endothelial differentiation. It accounts for about 1% of all soft tissue malignancies and most commonly arises in skin, soft tissue, breast, liver, bone and spleen [1].Primary pleural angiosarcoma (PPA) is a rare occurrence. Since its first description in 1943,[2] only 39 reported cases of PPA have been published [1-22]. Patients almost always die of the disease within months. Definite diagnosis is usually not possible using the examination of cytology or small biopsy specimens, but often requires that of decortication or resection specimens. The histologic picture of biphasic spindle and epithelioid tumor cells along with immunoreactivity to epithelial markers, such as cytokeratin and CK7, may lead to an erroneous diagnosis of mesothelioma or metastatic sarcomatoid carcinoma. Identifying areas showing vasoformative tendency and immunostains with endothelial markers, such as CD31, CD34, factor VIII and FLI-1, are diagnostically important.We describe herein a case of PPA, to highlight its aggressive clinical behavior and the diagnostic pitfalls.A 49 year-old-male patient presented with intermittent right chest pain for one month. The pain progressed with exertional dyspnea. He had a 10-year history of asthma under regular medical treatment and was an ex-smoker (half package-per-day for 20 years in the past) who quit 10 years ago. He did not have any history of asbestos exposure or tuberculous infection. In physical examination, breathing sounds were decreased at the right lung. Chest radiography and computed tomography revealed right-side loculated pleural effusion with pleural thickening but without mass lesion (Figure 1). Fine needle aspiration showed some bloody and sticky pleural effusion. The value of hematocrit of the effusion was 39.5% (peripheral blood hematocrit: 38.9%). Cytologic examin