Lung sarcoma is an extremely aggressive malignant tumor that develops from immature connective tissue elements of the lung. The symptoms of lung sarcoma are similar to the manifestations of lung cancer, but differ in more rapid progression. Subjective symptoms may include shortness of breath, cough, swallowing disorders, fever, severe fatigue, sweating. The syndrome of the superior vena cava, pleurisy, pericarditis, pneumonia, osteoarthropathy is often detected. For diagnostic purposes, X-rays, CT and MRI of the lungs, bronchoscopy, fine needle biopsy, etc. are performed. Surgical methods (radical and palliative), chemotherapy, radiotherapy are used to treat lung sarcoma.
C46.7 Kaposi’s sarcoma of other localizations
Lung sarcoma is a highly malignant lung tumor of mesodermal origin, the source of which is usually the connective tissue structures of the walls of the bronchi and interalveolar septa. Sarcoma refers to rare types of malignant lung tumors, it accounts for 1% of all types of lung cancer. Lung sarcoma differs from other malignant neoplasms by rapid growth and early metastasis. It most often affects young men (20-40 years old), but it can develop in people of any gender and age. In children, lung sarcoma proceeds especially aggressively, which is associated with the age-related activity of connective tissue growth. Oncology and pulmonology are engaged in the search for optimal ways to treat lung sarcoma.
Causes of lung sarcoma
The development of primary lung sarcoma can be initiated by various factors. It has been experimentally confirmed that in the etiology of sarcomas of various localizations, ionizing radiation, ultraviolet irradiation, chemicals, smoke and air pollution can come to the fore.
The group of increased risk for the occurrence of lung sarcoma includes smoking patients; workers in contact with industrial carcinogens (asbestos, aniline dyes, pesticides, etc.); persons living in industrial cities with a high content of exhaust gases and soot in the air. It is unsafe to abuse a tan, both natural (under the rays of the sun) and artificial (in a solarium). The role of burdened heredity has been proven: in the presence of family cases of sarcoma, the risk of its manifestation in other blood relatives is several times higher.
Secondary lung damage can be metastases of osteogenic sarcoma, uterine sarcoma, soft tissue sarcoma, breast, mediastinum, etc. In most cases, lung sarcoma is located in the peripheral parts, affecting the upper lobes, but it can also affect the entire lung; sometimes it is localized in large bronchi in the form of polypoid outgrowths. The tumor has the appearance of a massive node of a rounded or polycyclic shape, a soft consistency, white-pink color on the incision. Metastasis of sarcoma often occurs hematogenically.
By its origin, lung sarcoma is divided into primary (growing from its own lung tissues) and secondary (metastatic, spreading to the lungs from a distant primary focus – muscles, bones, genitals, etc.). Histologically, primary lung sarcomas can be highly differentiated (low degree of malignancy – with low mitotic activity of cells, high specific gravity of stromal elements) and low–differentiated (high degree of malignancy – with high rate of cell division, predominance of tumor elements, well-developed vascular network, foci of necrosis).
Highly differentiated lung sarcomas differ depending on the source of the blastomatous process and can be represented by the following types (in descending order of frequency):
- angiosarcoma – originates from the walls of blood vessels
- fibrosarcoma – is formed from bronchial and peribronchial connective tissue
- lymphosarcoma – develops from lymphoid tissue
- neurosarcoma – affects connective tissue elements of nervous tissue
- chondrosarcoma – comes from the cartilaginous elements of the bronchi
- liposarcoma – is formed from adipose tissue
- leiomyosarcoma and rhabdomyosarcoma – originate, respectively, from smooth muscle and striated muscle tissue
- hemangiopericytoma – arises from pericytes – cells that make up the walls of capillaries.
Undifferentiated lung sarcomas are divided into:
- fusiform cell
- round – cell
The staging of lung sarcoma is based on the extent of the tumor and involves the allocation of 4 stages:
- Stage I – a limited infiltrate or node in the lung up to 3 cm in diameter with no metastases;
- Stage II – a tumor of 3-6 cm in diameter with the presence of single metastases in the peribronchial lymph nodes and lymph nodes of the lung root;
- Stage III – a tumor larger than 6 cm in diameter with the presence of metastases in the lymph nodes of the mediastinum, invasion of the pleura
- Stage IV is a tumor of any size in combination with distant metastases.
Symptoms of lung sarcoma
The clinical picture of lung sarcoma resembles a lung cancer clinic, but unlike the latter, it develops more rapidly. Specific symptoms are determined by the stage, localization and histological structure of the tumor. With an intrabronchial type of tumor growth, bronchial obstruction may occur – in this case, the clinical picture resembles a clinic for central lung cancer.
In typical cases, patients are concerned about progressive shortness of breath, chest pain, cough with sputum and streaks of blood, fever, sweating. Due to constant weakness, fatigue, lack of appetite, general well-being suffers. With tumor invasion of the esophagus, dysphagia develops, with compression of venous trunks – the syndrome of the superior vena cava. The germination of the pleura is accompanied by the development of hemorrhagic pleurisy, the outer shell of the heart – hemorrhagic pericarditis.
Sometimes lung sarcoma is detected during a detailed examination for prolonged or recurrent pneumonia. In some cases, the clinical picture is dominated not by signs of lung damage, but by paraneoplastic syndrome (pulmonary osteoarthropathy) – periostitis, arthritis, joint pain, deformity of the fingers. In the later stages, cancer intoxication, cancer cachexia, anemia develops.
To confirm the diagnosis, an oncologist and a thoracic surgeon are consulted, anamnesis data are clarified, instrumental examinations are prescribed. Lung sarcoma can be suspected by the rapid progression of the tumor in young people. Radiation methods (radiography, CT of the lungs) are of leading importance in the detection of lung sarcoma. On radiographs, a rounded or oval shadow with uneven edges is determined, which is more often localized in the peripheral parts. With dynamic control, there is a rapid increase in the tumor. CT and MRI of the lungs make it possible to analyze the parameters of the tumor in more detail and stage the process.
With intrabronchial growth, polypoid sarcoma is well visualized during bronchoscopy. It has the appearance of a white-pink irregular-shaped formation without a capsule. The histological diagnosis is clarified by endoscopic biopsy or fine-needle transthoracic biopsy, which is carried out under the control of computed tomography. When exudative pleurisy is detected, it is advisable to conduct a pleural puncture with a cytological examination of the obtained material. In some cases, with lung sarcoma, diagnostic thoracoscopy or exploratory thoracotomy is resorted to.
Differential diagnosis of primary lung sarcoma is carried out with peripheral lung cancer, metastatic tumors, tuberculoma, echinococcosis and non-parasitic lung cysts, benign and malignant thymoma.
Treatment of lung sarcoma
When choosing a rational therapeutic tactic, the stage of lung sarcoma, its type and localization are taken into account. In operable cases, lobectomy or pulmonectomy with lymphadenectomy is performed. In the preoperative period, as a rule, a course of polychemotherapy is prescribed. Radiation therapy is usually used as part of a complex treatment (complements surgical and chemotherapeutic treatment), since lung sarcoma is less sensitive to radiotherapy. An innovative technology of selective internal radiotherapy (SIRT) is being introduced – the introduction of radioisotopes through a catheter into the vessels of the lung going to the tumor.
If radical resection is not feasible, palliative surgery may be performed to eliminate pathological symptoms and increase the short-term survival of patients. In addition, with inoperable tumors, chemotherapy can be prescribed separately or in combination with radiation therapy, immunochemotherapy.
Lung sarcoma is an oncological disease with a potentially unfavorable prognosis. A distinctive feature is the tendency to relapse and metastasis of lung sarcoma, which causes a low survival rate of patients with this diagnosis. The five–year survival rate at the beginning of treatment at the first stage is 50%, at the third – 20%. If a primary lung sarcoma is detected in the late stages or a secondary lung lesion, patients die within a few months.
- Pulmonary resection for metastatic sarcoma. Hughes F, Westphal K. Memphis Med J. 1949 May;24(5):95-7. link
- Development of sarcoma at site of serial transplantation of pulmonary tumors in inbred mice. Stewart HL, Grady HG, Ander Voint HB. J Natl Cancer Inst. 1947 Feb;7(4):207-25. link
- Case of fusocellular sarcoma of the lung. Verstraeten JM, Boels W. Acta Tuberc Belg. 1951 link
- Primary reticulum cell sarcoma of the lung arising in the wall of pulmonary cyst; a case report. Ransdell HT Jr, Bailey AW, Elisson RG. Am Surg. 1951 Aug;17(8):689-96. link
- Primary chondrosarcoma of the lung. Lowell LM, Tuhi JE. J Thorac Surg. 1949 Aug;18(4):476-83. link