Vascular Tumors of the Lungs
Contrary to their counterparts in other organ systems, primary vascular neoplasms of the lung are rare. Because of the rarity of these lesions, the clinical and radiological features are often mistaken for other, more common lesions. Both benign and malig
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Vascular Tumors of the Lungs
Introduction Contrary to their counterparts in other organ systems, primary vascular neoplasms of the lung are rare. Because of the rarity of these lesions, the clinical and radiological features are often mistaken for other, more common lesions. Both benign and malignant vascular tumors have been described. Before a diagnosis of a primary malignant vascular neoplasm can be rendered, metastasis from extrapulmonary sites will have to be excluded through thorough clinical and radiological investigations. Primary vascular tumors of the lungs include hemangioma, lymphangioma, angiolymphoid hyperplasia with eosinophilia, and capillary hemangiomatosis among the benign lesions and epithelioid hemangioendothelioma, angiosarcoma, and Kaposi’s sarcoma among the malignant ones (Table 8.1).
Hemangioma Clinical Features Hemangiomas are frequently seen in the soft tissue, skin, and liver and can occasionally occur in the subglottic region or in the mediastinum [1, 2]. In the lung, however, these tumors are rare. To date, only 24 cases of pulmonary hemangioma have been described in the English and Japanese literature [3, 4]. Hemangiomas have been described in patients of all ages with no specific sex predilection and can present as solitary or multiple lesions [3–9]. Patients are either asymptomatic or present with respiratory symptoms such as hemoptysis, pneumonia, or cyanosis [10–12]. Hemangiomas may arise anywhere in the lower respiratory tract from the lung parenchyma to the airways and the bronchial tree [13–16]. Although only few hemangiomas of the lung have been reported, a case with partial trisomy D has been described. In addition, it has been stated that pulmonary hemangiomas
may be complicated by conditions such as Kasabach-Merritt syndrome [17, 18].
Gross Features Macroscopically, hemangiomas present as well-demarcated or ill-defined hemorrhagic nodules, cysts, or cavernous spaces filled with hemorrhagic porous or thrombotic material [9–11, 19, 20]. The tumors may measure between 1 and 3 cm in size. Tumors with a bronchial component often display a polypoid growth pattern with protrusion into the bronchial lumen.
Histological Features Histologically, pulmonary hemangiomas are identical to those seen elsewhere in the body. They are encapsulated and lobulated masses composed of numerous cavernous or capillary vessels lined by bland endothelial cells [9, 10, 19, 20] (Fig. 8.1). Cytologic atypia and mitotic activity are usually absent, although rare mitotic figures may be present in isolated cases (Figs. 8.2 and 8.3). As is true for all other vascular tumors, the adjacent pulmonary parenchyma may show intra-alveolar hemorrhage and abundant hemosiderin-laden macrophages (Fig. 8.4).
Immunohistochemical and Molecular Features The endothelial cells of hemangioma show immunoreactivity for factor VIII related antigen, CD31, and CD34 [10, 12]. Due to the rarity of pulmonary hemangiomas, molecular investigations are lacking; however, studies performed on hemangiomas of the skin and soft tissue s
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