SESSION TITLE: Disorders of the Pleura Global Case Reports
SESSION TYPE: Global Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: Solitary fibrous tumors (SFTs) are uncommon soft tissue tumors and they are rarely originate from pleura. These tumors are frequently observed in middle-aged, with no sex predilection. Most of them behave as slow-growing, painless masses. Usually they are found incidentally on chest radiography. Although most SFTs show benign behavior, some have malignant potential. Benign SFTs can be cured by complete surgical resection. Since 1931, about 800 cases of such tumors have been reported (1). Immuno-histochemical analysis is used to make the diagnosis. The median survival for patients with all types of SFT has been reported to be 24 years (2).
CASE PRESENTATION: We reviewed two patients who had undergone a surgical resection for treatment of benign solitary fibrous tumors of pleura. The history of the them was unremarkable and none had familial disease, history of asbestos exposure or smoking. They were admitted to the hospital with nonspecific signs and masses were found incidentally on chest radiography. Case1: A 65-year-old female patient. 11x8.5x3 cm sized, gray-white colored, soft, fragile and partially cystic mass was detected in right lung middle zon. Case2: A 77-year-old male patient. 14x11x5 cm sized mass has same morphologic features with first patient’s mass and it localized in left lung diaphragmatic side. Complete resection was performed through thoracotomy, which for these cases involved video-assisted thoracic surgery (VATS). On microscopic examination non-atypical spindle-shaped tumor cells with vesicular nuclei were seen on a collagenous background. Hypocellular and hypercellular areas and hemangiopericytoma-like vascular pattern were observed in these cases. Low mitotic rates and Ki67 proliferation indexes were detected in both cases (Figure 1). On immuno-histochemical analysis, we found that mesenchymal markers such as CD34, bcl-2 and vimentin were positive (Figure 2), whereas S-100, desmin and C Kit were negative.
DISCUSSION: Most SFTs arise from the submesothelial tissue of the pleura. More than 50 % of benign SFTs are asymptomatic. Chest radiography and CT are not specific for the diagnosis of SFT but espectially CT can show the size and location of them and help in surgical planning. The primary therapy for all SFTs is complete surgical resection. Because of the clinical features and radiographic appearance are not specific, SFTs are usually misdiagnosed, such as thymic neoplasia, teratoma, neurogenic tumor, mesothelioma or lung cancer. Immunohistochemistry is very usefull to differentiate SFTs from others. CD34 is positive in most SFTs and negative in most other pulmonary tumors. The SFTs are generally vimentin positive and cytokeratin negative; in contrast, mesothelioma is cytokeratin positive and often vimentin negative. In addition, bcl-2 is strongly expressed in SFTs, and can be used as a diagnostic marker in CD34- negative tumors. Although hemangiopericytomas are CD34-positive, bcl-2 is not or poorly expressed. Most SFTs are CD99 positive and S-100 negative. The prognosis of benign SFTs of the pleura with complete surgical resection can be excellent, while careful follow-up is still necessary (3).
CONCLUSIONS: Most SFTs of pleura and lung are benign mesenchymal tumors. Immunohistochemistry is extremely useful in differentiating SFTs from mesotheliomas and other mesenchymal tumors. Morphological and histological features are important in predicting their clinical behaviour. Although patients with SFTs can be cured by complete resection of the tumor, they need long-term follow-up owing to the possibility of recurrence.
Reference #1: 1-Robinson LA. Solitary fibrous tumor of the pleura. Cancer Control 2006;13:264-9.
Reference #2: 2-Harrison-Phipps KM, Nichols FC, Schleck CD, et al. Solitary fibrous tumors of the pleura: results of surgical treatment and long-term prognosis. J Thorac Cardiovasc Surg 2009;138:19-25.
Reference #3: 3- Travis WD, Brambilla E, Muller-Hermelink HK, Harris CC (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Lung, Pleura, Thymus and Heart. IARC Press: Lyon 2004
DISCLOSURE: The following authors have nothing to disclose: Ebru Tastekin, Inci Kutlu, Fulya Oz Puyan, Ali Kemal Kutlu
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