Secondary tumor lesions of the costal pleura and chest wall are the result of either the direct spread of lung cancer or the result of metastasis.
Peripheral carcinoma, which is localized in the cloak of the lung, can grow into these anatomical structures. In this case, it is called corticopleural cancer.
Radiographically, it is displayed in a semi-oval shape by shading, which is adjacent to the chest wall with a wide base. and forms obtuse angles with it. The pleura at this level is thickened, the image of the soft tissues of the chest wall loses its structure, an effusion appears in the pleural cavity. However, these symptoms are not always so demonstrative. In addition, it should be borne in mind that changes in the costal pleura during subpleural localization of lung cancer do not necessarily represent its continued growth. This may be reactive aseptic inflammation of the pleura, accompanied by the development of pleural adhesions that do not contain tumor cells. Radiological differentiation of these processes is extremely difficult. Unconditional sign of tumor invasion of the chest wall is only the presence of the destruction of its bone elements. But it does not occur often.
The most well-known variant of corticopleural cancer is a Pencost tumor originating from the upper pulmonary sulcus. At the same time on radiographs is determined by the shading of the apex of the lung, the lower contour of which is arcuate convex, and the upper merges with the chest wall and can not be traced. Pathognomonic sign is the destruction of the posterior parts of the I, II ribs, transverse processes and lateral surfaces of the bodies of the lower cervical and upper thoracic vertebrae.
In general, the sensitivity of traditional X-ray studies in recognizing the germination of lung cancer in the costal pleura and chest wall is still small and does not exceed 30%. Significantly large possibilities in this regard are possessed by new ray methods: echography — 43%, CT and MRI — about 60% (EV Lovagin et al., 1996). Many of the signs of tumor recognition on the pleura and chest wall that are detected, however, are similar to the known radiological symptoms (thickening of the pleura and soft tissues, loss of differentiation of intermuscular fascial spaces, fluid in the pleural cavity, destruction of bone elements), but they are much more accurate even when slight severity of changes. The most important thing isthat they are able to directly visualize the tumor infiltration of various structures of the chest wall and establish its connection with the intrapulmonary process. Echographically, this is provided on the basis of changes in tissue echogenicity characteristic of the tumor, with CT, due to its high sensitivity to the gradients of densitometric tissue density, with MRI based on differences in radio signal intensities from the tumor tissue (high level) and chest wall muscles (low level). Equally important is the possibility of equally reliable exclusion of germination of a lung tumor in the chest wall. In particular, such a computed tomographic symptom is the preservation of extrapleural fat layer at the tumor level.
The metastases of lung cancer in the chest wall are very similar to corticopleural cancer. However, in these cases, the severity of the intrapulmonary component of the tumor is much less, and its main body is in the chest wall.
The metastatic lesion of the costal pleura in lung cancer has a miliary-disseminated character and is accompanied by pleural effusion. For its detection, as a rule, it turns out to be a fairly common radiography, supplemented in unclear cases with lateralography. Reliable detection even
The minimum amount of fluid in the pleural cavity provides echography and CT. However, it must be borne in mind that the presence of pleural effusion is not in itself evidence of a secondary tumor lesion of the pleura. The cause of exudation to the pleural cavity in lung cancer may be blocking the flow of lymph (intrapulmonary lymphatic vessels, intrathoracic lymph nodes, thoracic lymphatic duct). Another mechanism of effusion formation is a decrease in intrapleural pressure due to atelectasis of a part of the lung during obstruction of a large bronchus with a tumor. Hydrothorax may also occur due to an increase in hydrostatic pressure in the large and small circulation in case of tumor exudative pericarditis. In addition, the causes of pleural extravasation may be hypoproteinemia,developing in many cancer patients, and parkrokrosnaya pulmonary infection. Bilateral lesion of the pleura in lung cancer usually indicates liver damage and the spread of metastases from it to the pleura of the opposite side.
An important advantage of modern radiation methods is not only the ability to detect fluid in the pleural cavity, but also a reliable assessment of the pleural leaf itself. With its metastatic lesion, it is possible to detect an uneven thickening of the pleural leaves, the presence of multiple nodules on them, the size of which usually does not exceed 1 cm. With CT, these changes are especially demonstrative in the interlobar pleura, with ultrasound and MRI – in the bone.
In general, the priority method of radiological diagnosis of lung cancer, including the determination of its intrathoracic distribution, in our opinion, should be recognized as computed tomography, which, with its availability, should completely replace linear tomography. CT allows you to simultaneously assess the condition of almost all organs and anatomical structures of the chest wall, and with a high degree of accuracy, reaching 90%. In 80% of patients with lung cancer, this method, when compared with the results of traditional X-ray examination, provides additional information, which in most cases is decisive in determining the stage of the tumor process. The use of CT significantly reduces and simplifies the diagnostic period, eliminates the need for the use of complex, invasive,burdensome for patients with other radiological methods of research and it turns out, ultimately, more economical.
Magnetic resonance imaging can be used at the final stage of the radiation study, mainly with questionable CT data on the invasion of lung cancer on the vessels of the mediastinum and on the chest wall.
According to the data, the use of CT and MRI in lung cancer reduced the frequency of test thoracotomy by 5 times — from 25 to 5%. If CT and MRI can not be used, a more accessible echography should be included in the mandatory volume of lung radiography. The range of tasks that she is capable of solving, as compared with CT and MRI, is, of course, much narrower. Nevertheless, it is quite informative in the diagnosis of secondary tumor lesions of the heart, mediastinal vessels, chest wall, in establishing metastasis to separate groups of mediastinal lymph nodes.
Among the tasks solved during the examination of patients with lung cancer, one of the priorities is the elimination of distant tumor metastases.