Abstract Objective To investigate the X-ray signs that can suggest the diagnosis of carcinomatous lymphangitis on chest plain radiographs. Methods The X-ray and HRCT signs of 37 cases of pulmonary carcinomatous lymphangitis confirmed by bronchoscopic biopsy, pleural biopsy or open lung biopsy were retrospectively analyzed, and the X-ray signs that could suggest carcinomatous lymphangitis were sought. Results Among the 37 X-ray manifestations of carcinomatous lymphangitis of the lung, 37 cases had multiple thickened bronchovascular bundles in both lungs, 28 cases had widely distributed irregularly thickened Kirschner A lines in both lungs, 19 cases had widely distributed reticular and reticular nodular shadows (irregularly thickened Kirschner C lines) in both lungs, 15 cases had multiple irregularly thickened Kirschner B lines in both lungs, 18 cases had enlarged hilar lymph nodes, 16 cases had irregularly thickened pleura, and pleural effusion in 9 cases. Conclusion The imaging diagnosis of pulmonary carcinomatous lymphangitis is best made by HRCT, but a good quality chest X-ray plain film can provide some useful signs, and recognizing these signs can avoid missing the diagnosis and provide a basis for further confirmation. Lei Zhidan, Department of Radiology, Henan Provincial People’s Hospital
Keywords tumor metastasis, lymphangitis; radiography.
Body layer photography, X-ray computer; Pathology
Pulmonary lymphangitic carcinomatosis: some noticeable thoracic X-ray film imaging signs
LEI Zhi-dan, JIA Wu-lin, WEN Ze-jun , SHI Da-peng , LU Yun-sheng
(Department of Radiology, Henan Provincial People’s Hospital, Zhengzhou 450003, China)
Abstract: Objective To study the X-ray signs of pulmonary lymphangitic carcinomatosis (PLC) that thoracic plane film can supply. Methods The X-ray and HRCT signs of 37 cases’ PLC which were proved by bronchoscopic or pleural or open-lung biopsy were retrospectively analyzed, and some X-ray signs that could clued to PLC were found. Key words: Carcinomatoses, lymphangitis; Radiography; Tomography, X-ray computed; Pathology Pulmonary lymphangitic carcinomatosis (PLC) is a specific form of intrapulmonary metastatic carcinoma characterized by diffuse growth of metastatic cancer cells within and outside the lymphatic vessels, accounting for 6% to 8% of intrapulmonary metastases [1. 2]. The prognosis of this disease is extremely poor, with 50%-85% of patients surviving 3-6 months [3], while Gao Zhansheng [2] reported a mean survival of 13 months. Therefore, the diagnosis and treatment of PLC has increasingly attracted the attention of scholars. In clinical work, X-rays are easily confused with nodular disease, tuberculosis, lymphoma intrapulmonary infiltrates, chronic bronchitis, interstitial pneumonia and other interstitial lung lesions, so it is more difficult to confirm the diagnosis. However, careful observation and analysis on good quality chest radiographs can reveal helpful signs suggestive of the diagnosis of PLC, thus providing a basis for further examination. Although the author has seen some literature on the x-ray diagnosis of PLC [3.4], he has not seen any reports of valuable x-ray signs by comparison with HRCT. In this paper, we describe some signs that are valuable in suggesting the diagnosis of PLC by retrospectively analyzing the X-ray and HRCT data of pathologically confirmed cases. 1 Materials and methods 1.1 General data In this group, there were 37 cases, 21 males and 16 females, aged 38-71 years, with an average age of 55 years. Clinical symptoms:① 31 cases of dyspnea, with progressive worsening dyspnea of varying degrees;② 29 cases of cough, mostly irritating dry cough, with yellow sputum when combined with infection;③ 5 cases of hemoptysis, all with blood in the sputum;④ 3 cases of hypothermia.31 cases of diminished breath sounds, 25 cases of cyanosis, 7 cases of turbid sounds on chest percussion, 4 cases of scattered end-inspiratory fine Velcro mats on auscultation in both lungs, 6 cases without symptoms and signs. Pulmonary function tests were performed in 15 cases, of which 13 had restrictive ventilation and 7 had diffusion dysfunction. We can avoid missed diagnosis by acquiring these signs, and it can supply the valuable foundation of cli. 18 cases with varying degrees of hypoxemia and 4 cases with hypocapnia were examined by blood gas analysis. 25 cases were confirmed by bronchoscopic biopsy, 8 cases by pleural biopsy and 4 cases by open lung biopsy pathology. 1.2 Imaging methods All 37 PLC cases had chest X-ray plain film, CT and HRCT. CT scan was performed by GE/Light Speed Plus 4 multilayer spiral CT machine. Plain layer thickness of 7.5 mm, pitch factor of 1.5:1, reconstruction interval of 5 mm, standard algorithm reconstruction, matrix 512×512, range from the entrance of the thorax to the base of the lung, observed by lung window and mediastinal window; HRCT examination layer thickness of 1.25 mm, layer spacing of 10 mm, bone algorithm image reconstruction, from the level of the aortic arch to the diaphragm, observed by lung window. 1.3 Analysis method Two radiologists who were unaware of the results and experienced in the field carefully observed the X-ray signs of the 37 PLC cases, focusing on the X-ray changes of the pleura, keratoconus, bronchovascular bundle, hilar and mediastinum, and recorded and analyzed them to arrive at the diagnosis. The CT and HRCT signs of PLC were then analyzed jointly by two other radiologists who were unaware of the results and experienced in the field, focusing on the CT manifestations of the pleura, lobular core, intralobular septa, lobular septa, bronchovascular bundles, hilar and mediastinal lymph nodes, and arriving at a diagnosis. Then, the X-ray and HRCT signs of PLC were compared and analyzed by a radiologist to seek X-ray signs that could suggest cancerous lymphangitis. 2 Results 2.1 Primary tumors of PLC were derived from peripheral lung cancer in 13 cases (13/37), central lung cancer in 2 cases (2/37), breast cancer in 11 cases (11/37), gastric cancer in 7 cases (6/37), and pancreatic cancer in 4 cases (4/37), respectively. 2.2 X-ray plain film Among the 37 cases of PLC, 37 cases had multiple thickening of bronchovascular bundles in both lungs, 28 cases had widely distributed irregular thickened Kirschner A lines in both lungs, 19 cases had widely distributed reticular and reticular nodular shadows (irregular thickened Kirschner C lines) in both lungs, 15 cases had multiple irregular thickened Kirschner B lines in both lungs, 18 cases had enlarged hilar lymph nodes, 16 cases had irregular thickened pleura, and 9 cases had pleural effusion. The specific distribution and X-ray signs of the 37 cases of PLC are shown in Table 1. Table 1 Distribution and radiographic signs of PLC in 37 cases (cases) thickened grams bronchial blood network nodules thickened grams pleural irregularities pleural cavity peripheral masses and bronchial air hilar masses and bronchial air hilar lymph A line, thickened bundles, shadows, B line, thickened fluid, thickened vascular bundles, enlarged nodes. Left lung 28 37 17 11 16 6 3 2 16 Right lung 25 36 19 15 13 9 10 0 18 2.3 CT and HRCT The main signs of the 37 PLC cases were: (1) pleural nodules; (2) core lobular nodules; (3) intralobular fine mesh nodular shadow; (4) small bead-like thickening of lobular septa; (5) bead-like thickening of bronchial vascular bundles; (6) enlarged hilar and/or mediastinal lymph nodes; (7) pleural effusion; (8) peripheral lung cancer with bead-like thickening of bronchial vascular bundles; (9) central lung cancer with bead-like thickening of bronchial vascular bundles. The diagnosis was correct in 34 cases, about 91.9% (34/37). the specific CT presentation of 37 PLC cases is shown in Table 2. Table 2 Distribution and CT signs of 37 cases of PLC (cases) Pleura Lobular nucleus Lobular septum Bronchial blood Pulmonary hilar lymph Thorax Peripheral type lung cancer with branches Central type lung cancer with branches Nodules Heart nodules Reticulonodular shadow Thickening of bundles Enlarged nodes Fluid accumulation Thickening of tracheal vascular bundles Thickening of tracheal vascular bundles Left lung 31 15 28 33 37 28 8 3 2 Right lung 26 17 25 31 37 31 11 10 0 2.4 Pathological manifestations of open lung biopsies in 4 cases The lymphatic vessels in the core, intralobular, subpleural interstitium, interlobular septa and bronchial vascular bundles were found to be filled with cancer cells, growing in clusters, with lymphatic vessels stagnating and causing lumen expansion, accompanied by interstitial edema, interstitial tumor cell infiltration and fibroinflammatory cell infiltration of varying degrees. 3 Discussion PLC refers to the pathological changes such as cancer cell infiltration inside and outside the lymphatic vessels, lymphatic dilation, perilymphatic interstitial edema and fibroinflammatory cell infiltration caused by lymphatic metastasis within the lungs of malignant tumors, hence the name [2. 5. 6]. The disease is mostly seen in intrapulmonary metastases of lung cancer, breast cancer and gastric cancer [2. 5l, but also in intrapulmonary metastases of many malignant tumors such as colon cancer, cervical cancer and thyroid cancer [7]. 3.1 Anatomical basis and pathogenesis of PLC 3.1.1 Anatomical basis of PLC The lymph nodes of the lungs were divided into superficial and deep groups. The superficial group was distributed on the deep surface of the pulmonary pleura, forming lymphatic filaments that converged into lymphatic vessels to inject into the pleural lymph nodes, and then into the hilar lymph nodes or anterior and posterior mediastinal lymph nodes, respectively; the deep group was located around the bronchi and blood vessels at all levels, forming lymphatic filaments that converged into lymphatic vessels of the lung, and injected into the hilar lymph nodes through the pulmonary lymph nodes arranged along the bronchovascular bundles in the lung, and then further injected into the tracheobronchial group lymph nodes, and Paratracheal lymph nodes around the trachea. Moreover, the endothelial cells of the lymphatic vessels are extremely sparsely arranged and lack a basement membrane outside the endothelial cells, which are fixed in the stroma by elastic fibrils, keeping the lymphatic vessels in a dilated state, so that the intertissue fluid converges into the lymphatic vessels with living valves and then eventually returns to the venous system via the lymphatic circulation. This structural feature determines that the tumor is more likely to enter the lymphatic system and cause metastasis [8-10]. 3.1.2 Pathogenesis of PLC Most scholars [2.4. 5] have favored the following points: (1) the tumor metastasizes to small capillaries via bloodstream and then invades the lymphatic vessels, and then reaches the hilar lymph nodes or peripheral lymph nodes via lymphatic vessels, and this route may or may not be accompanied by enlargement of hilar and mediastinal lymph nodes. The lymphatic vessels were obstructed by mediastinal or hilar lymph node compression, resulting in lymphatic dilation and eccentric reflux of lymphatic fluid, which led to the metastasis of tumor cells to the peripheral lung, and this pathway was often accompanied by hilar and mediastinal lymph node enlargement. (3) Pulmonary interstitial edema, cancer cell infiltration and interstitial fibroblastic reaction around the lymphatic vessels. In this group, the PLC presentation of 11 cases of breast cancer, 7 cases of gastric cancer and 4 cases of pancreatic cancer indicated that the pulmonary lymphatic tract metastasis of extra-pulmonary tumors followed the above mechanism. In our group, PLC occurring in 13 cases of peripheral type lung cancer and 2 cases of central type lung cancer were seen in the form of beaded thickening of bronchovascular bundles from the mass to the hilum. Therefore, it can be speculated that the lymphatic vessels in the peripheral part of the tumor are more obviously hyperplastic, and the tumor cells can easily enter them, and then merge into the lymphatic vessels around the bronchial vascular bundles and cause them to thicken in a bead-like manner, and then PLC occurs due to the obstruction of the lymphatic vessels by mediastinal or hilar lymph node compression, or PLC occurs through the first pathway mentioned above, which is consistent with the study of Shen Xiao-h et al [8-10]. 3.2 The main signs of PLC that are valuable in chest radiographs 3.2.1 Bronchovascular bundle thickening: the X-ray plain films of 36 of the 37 cases of PLC in this group showed irregular thickening of the bronchovascular bundles in both lungs (Figure 1), while the HRCT of the corresponding cases showed bead-like thickening of the bronchovascular bundles (Figure 2), and the HRCT of all 37 cases showed bead-like thickening of the bronchovascular bundles, thus bronchovascular bundle thickening was the X-ray and HRCT of PLC important signs, which is consistent with the literature [11]. 3.2.2 Irregularly thickened Kirschner A and B lines (Figure 3): Among 37 cases of PLC, X-ray plain radiographs showed 28 cases of irregularly thickened Kirschner A lines, while 15 cases of irregularly thickened Kirschner B lines showed small bead-like thickening of diffusely distributed lobular septa on HRCT (Figure 4.5), which also indicated that irregularly thickened Kirschner lines were an important X-ray sign of PLC. 3.2.3 Reticular and nodular shadows: the pathological basis of this sign [12] is interstitial thickening, nodular thickening of the interstitium or nodules plus interstitial thickening. 20 cases of PLC in our group had this change on chest plain film (Figure 6), while HRCT of the corresponding cases showed nodular thickening of the intralobular interstitium and interlobular interstitium with lobular core nodules (Figure 7). Therefore, reticular and reticulonodular shadows are also one of the important signs of PLC. 3.2.3 Pleural irregular thickening: X-ray plain radiographs in this group of PLC showed irregular thickening in 25 cases (Figure 8.9), and HRCT showed pleural nodules or subpleural nodules in 31 cases (Figure 10), which may be related to the pathway of lymphatic drainage from the superficial group to the pleura. In this group, 11 cases of breast cancer showed a larger rate on chest radiograph, and thus it was also one of the important X signs of PLC. 3.2.4 Pleural effusion and enlarged hilar and mediastinal lymph nodes: In this group, there were 12 cases of pleural effusion, accounting for 30%, similar to that reported by Cai Hourong [7], and 31 cases of enlarged hilar and mediastinal lymph nodes, of which 18 cases (48.6%) were shown by X-ray. Among them, 10 cases of pleural effusion and 18 cases of hilar and mediastinal lymph node enlargement were combined with thickened bronchovascular bundles, irregularly thickened Kirschner A and B lines and reticular and reticular node-like shadows, and the X-ray diagnosis was correct. Therefore, although pleural effusion and enlarged hilar and mediastinal lymph nodes are not unique to PLC, the combination of these changes should indicate PLC. 3.3 Observation methods and considerations for chest X-ray plain films 3.3.1 Observation methods: ① X-ray plain films must be required to be high-quality chest films; ② observation should be comprehensive and focused, focusing on whether the lymph nodes in the hilum and mediastinum are enlarged, whether the bronchovascular bundles are thickened, whether the keratoconus lines are thickened, whether there are reticular and reticular shadows, whether there are pleural nodules and pleural effusions; ③ if the examination is CR or DR, different window widths and window positions should be appropriately adjusted to observe the This is consistent with the literature. 3.3.2 Precautions: ①In this group of PLC, 26 cases had all the above-mentioned X-ray signs and the diagnosis was correct, so the more the above-mentioned signs are, the more valuable they are, and if they are to suggest the diagnosis, they should have more than two of the above-mentioned signs; ②If the X-ray suggests PLC, HRCT examination or biopsy is also needed; ③The thickening of the above-mentioned structures should be irregular and consistent with the nodular thickening on HRCT, which should be consistent with Interstitial pulmonary edema and other diseases with negative interface signs (smooth contact surface between the interstitium and alveoli) should be differentiated. 4. Other diseases with positive interface signs, such as nodular disease, malignant lymphoma, and tuberculous coal workers’ pneumoconiosis, should also be differentiated. 5. The X-ray diagnosis should be closely integrated with the clinical picture, in addition to HRCT. In conclusion, the X-ray plain film signs and HRCT signs of PLC have certain characteristics, especially HRCT, which shows the fine structures clearly and can reflect the pathological changes of PLC, and is an effective means to diagnose the lymphatic pathway metastasis of malignant tumors in the lung. 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