Fig. 2.1 Lung mass representing a lung adenocarcinoma in a 75-year- old man. (a, b) Lung window of transverse and coronal reformatted images of CT scans shows a 42-mm-sized mass (arrows in a and b) in the right middle lobe. (c) Gross specimen obtained with right middle lobectomy demonstrates variable appearances of tumor, namely, white

and yellow areas, respectively, with lobulated margin (arrows). This is due to heterogeneous subtypes of adenocarcinoma. (d) LowmagniÞcation (×40) photomicrograph discloses papillary pattern of tumor growth (arrows) with background of lepidic growth pattern

Pulmonary Sarcoma

Pathology and Pathogenesis

True primary sarcomas of the lung are rare, and they include Kaposi sarcoma, Þbrosarcoma, leiomyosarcoma, epithelioid hemangioendothelioma, malignant Þbrous histiocytoma, rhabdomyosarcoma, chondrosarcoma, synovial sarcoma, and pulmonary artery sarcoma.

Symptoms and Signs

In patients with primary pulmonary sarcoma, clinical symptoms are nonspeciÞc. Cough, dyspnea, chest pain, and

hemoptysis may develop, depending on the size and the location of the lesions.

CT Findings

Primary pulmonary sarcomas usually manifest as large and heterogeneous masses on CT (Fig. 2.3), and the different histologic types of sarcomas are frequently indistinguishable at imaging analysis. Malignant Þbrous histiocytoma originates from the muscles of the chest wall and seldom from the lungs, mediastinum, or pleura. They appear as well-deÞned, smooth or lobulated soft tissue masses with heterogeneous enhancement and rarely contain calciÞcations [13]. Pleuropulmonary synovial sarcoma often demonstrates a

Fig. 2.2 Lung mass representing a typical carcinoid in a 24-year-old man. (a) Enhanced CT scan (5.0-mm section thickness) obtained at level of the inferior pulmonary veins shows a 60-mm-sized enhancing mass in the right middle lobe. Also note internal ossiÞcations (arrows). (b) Gross specimen obtained with right middle lobectomy demonstrates

well-marginated mass growing with compressive rather than inÞltrative manner to adjacent lung parenchyma. Also note internal ossiÞcations (arrows). (c) High-magniÞcation (×200) photomicrograph displays trabeculae of uniform tumor cells separated by numerous vascular septa. Also note connective tissue containing the bones (arrows)

well-deÞned mass with patchy low attenuation on unenhanced CT images and heterogeneous enhancement on contrast-enhanced CT images [14]. CalciÞcation is a common Þnding in synovial sarcoma at para-articular sites but a rare Þnding in pleuropulmonary synovial sarcoma.

lated with the myxoid or collagenous elements, and heterogeneous enhancement on contrast-enhanced CT is correlated with areas of hemorrhage, necrosis, and cystic change [14].

CT–Pathology Comparisons

Most pulmonary sarcomas derive from smooth muscle or fibrous tissue; therefore, they show mild or marked enhancement on contrast-enhanced CT. On CTÐpathology correlations of pleuropulmonary synovial sarcoma, patchy low-density areas on unenhanced CT are corre-

Patient Prognosis

Surgery is the most effective treatment. Chemoradiation therapy may be the best treatment option in unresectable case. Prognosis mainly depends on whether complete surgical resection is accomplished. Therefore, early diagnosis is the most important prognosis-determining factor. Overall 5-year survival has been reported to be 40Ð50 % [15, 16].

Fig. 2.3 Lung mass proved to be an undifferentiated pulmonary sarcoma in a 49-year-old man. (a, b) Mediastinal window of transverse (a) and coronal (b) reformatted images of CT scans shows a 28-mm-sized nodule (arrows in a and b) in right apical area. Initially nodule was interpreted as a neurogenic tumor. (c, d) CT scans obtained 7 months after a and b demonstrate markedly enlarged mass measuring 90 mm in diameter

at this time. Also note tumor embolus (arrow in d) in a branch of the right superior pulmonary vein. (e) Gross pathologic specimen obtained with right upper lobectomy discloses a large mass containing necrotic area (arrow) in apex of lobe. (f) High-magniÞcation (×200) photomicrography discloses tumor cells showing round shape with high pleomorphism and marked mitotic activity. Inset: positive staging for CD99