Sarcomatoid carcinoma of the lung
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: Primary sarcoma of the lung; Lung sarcoma; Sarcomatoid tumor of the lung
Overview
Sarcomatoid carcinoma of the lung is a rare histologic subtype of non-small cell lung cancer. Sarcomatoid carcinoma of the lung is a "sarcoma-like" carcinoma neoplasm. The overall prevalence of sarcomatoid carcinoma of the lung is 0.1% to 0.4% of all lung malignancies.[1]
Historical Perspective
- In 1988, EGFR gene mutations were first identified in the pathogenesis of sarcomatoid carcinoma of the lung.
Classification
- Sarcomatoid carcinoma of the lung may be classified according to WHO classification into 5 subtypes:
- Pleomorphic carcinoma
- Spindle cell carcinoma
- Giant cell carcinoma
- Carcinosarcoma
- Pulmonary blastoma
Pathophysiology
- The pathogenesis of sarcomatoid carcinoma of the lung is characterized by a rare epithelial origin, and morphologic features suggestive of a malignant mesenchymal tumour.
- Sarcomatoid carcinoma of the lung arises from epithelial cells but has morphologic features suggestive of a malignant mesenchymal tumor.
- The EGFR gene and K-ras mutations mutation has been associated with the development of sarcomatoid carcinoma of the lung.
- On gross pathology, a large sized mass lesion, with upper lobe and peripheral location are characteristic findings of sarcomatoid carcinoma of the lung.
- On microscopic histopathological analysis, sarcomatous components are characteristic findings of sarcomatoid carcinoma of the lung.
Causes
- Sarcomatoid carcinoma of the lung may be caused by a mutation in the EGFR and K-ras genes.
Differentiating sarcomatoid carcinoma of the lung from other Diseases
- Sarcomatoid carcinoma of the lung must be differentiated from other diseases that cause cough, weight loss, hemoptysis, and dyspnea among adults, such as:
- Tuberculosis
- Adenocarcinoma of the lung
- Pulmonary fungal disease
- Lung abscess
Epidemiology and Demographics
- The prevalence of sarcomatoid carcinoma of the lung is approximately 0.4 cases per 100,000 individuals worldwide.
- The overall prevalence of sarcomatoid carcinoma of the lung is 0.1% to 0.4% of all lung malignancies.[1]
Age
- Sarcomatoid carcinoma of the lung is more commonly observed among patients aged 50 to 75 years old.
- Sarcomatoid carcinoma of the lung is more commonly observed among elderly patients and adults
Gender
- Males are more commonly affected with sarcomatoid carcinoma of the lung than females.
Race
- There is no racial predilection for sarcomatoid carcinoma of the lung.
Risk Factors
- Common risk factors in the development of sarcomatoid carcinoma of the lung are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].
Natural History, Complications and Prognosis
- The majority of patients with sarcomatoid carcinoma of the lung remain asymptomatic for [duration/years].
- Early clinical features include chronic coughing, chest pain, and fatigue.
- If left untreated, the majority of patients with sarcomatoid carcinoma of the lung may progress to develop lymphatic invasion, distant metastasis, and
- Common complications of sarcomatoid carcinoma of the lung include respiratory failure, pneumonia, and distant metastasis.
- Prognosis is generally poor, and the average 5- survival rate of patients with sarcomatoid carcinoma of the lung is approximately 12%.
Diagnosis
Diagnostic Criteria
- The diagnosis of sarcomatoid carcinoma of the lung is made by lung biopsy.
- Biopsy findings associated with sarcomatoid carcinoma of the lung will depend on the subtype of tumor histology, common findings include:
- Pleomorphic carcinoma subtype
- Spindle cell carcinoma subtype
- Giant cell carcinoma subtype
- Carcinosarcoma subtype
Symptoms
- Common symptoms of sarcomatoid carcinoma of the lung may include the following:
- Shortness of breath
- Fatigue
- Chest pain
Physical Examination
- Patients with sarcomatoid carcinoma of the lung usually appear older in age in relation to their chronological age.
- Physical examination may be remarkable for:
Inspection
- Performed in the anterior chest/posterior chest
- Hoarseness
- Rapid rate of breathing
Auscultation
- Present pleural friction rub
- Present egophony
- Crackling or bubbling noises
- Present whispered pectoriloquy
- Decreased/absent breath sounds
Percussion
- Hyporesonance
- Dull percussion
- Tactile fremitus
- Reduced chest expansion
Laboratory Findings
- There are no specific laboratory findings associated with sarcomatoid carcinoma of the lung.
Imaging Findings
- CT scan is the imaging modality of choice for sarcomatoid carcinoma of the lung.
- On CT, sarcomatoid carcinoma of the lung is characterized by the following findings:
Other Diagnostic Studies
- Sarcomatoid carcinoma of the lung may also be diagnosed using bronchoscopy, mediastinoscopy, transthoracic percutaneous fine needle aspiration.
Treatment
Medical Therapy
- There is no treatment for sarcomatoid carcinoma of the lung; the mainstay of therapy is supportive care.
- The mainstay of therapy for sarcomatoid carcinoma of the lung is [medical therapy 1] and [medical therapy 2].
- [Medical therapy 1] acts by [mechanism of action1].
- Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].
Surgery
- Surgery is the mainstay of therapy for sarcomatoid carcinoma of the lung.
- [Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of sarcomatoid carcinoma of the lung.
- [Surgical procedure] can only be performed for patients with [disease stage] sarcomatoid carcinoma of the lung.
Prevention
- Effective measures for the primary prevention of sarcomatoid carcinoma of the lung include CT screening.
- According to the U.S. Preventive Services Task Force (USPSTF), screening for lung cancer by low-dose computed tomography is recommended every year among smokers who are between 55 to 80 years old and who have history of smoke 30 pack-years or more and either continue to smoke or have quit within the past 15 years (grade B recommendation)
- Once diagnosed and successfully treated, patients with sarcomatoid carcinoma of the lung are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].