Primary Pulmonary Collision Tumor: One Case Report And Review Of The Literature

Objective:To improve the knowledge of pulmonary collision tumor in diagnosis, differential diagnosis and treatment methods.Materials and methods:A case of primary pulmonary collision tumor patient is reported in qilu hospital of shandong university, relevant literatures—10 patients with pulmonary collision tumor and 74 patients with collision tumor of other organs are reviewed.Results:Collision tumor is a rare disease, pulmonary collision tumor is more rare with the unclear pathogenesis.there are several hypothesis about the disease: 1) accidentally concurrent, namely two primary tumor accidental happening at the same time and adjacent to each other.2) the presence of the first tumor changes the local microenvironment, thus facilitating the development of the second primary tumor or seeding of the metastatic tumor cells.3) the differentiation of multipotential stem cells, thus showing different histologic type. The 50-70 years old age men are prone to get the disease more than women. The manifestations of the disease are nonspecific compared with single lung cancer, such as fever, Cough, blood-stained sputum, haemoptysis, chest pain, dyspnea with Weight loss, anorexia, fatigue. Most of pulmonary collision tumor can't be diagnosed before operation. Conventional detection is not specific, so the disease is easy to misdiagnosis. The diagnosis is determined mainly by postoperative pathologic detection, only a few cases can be diagnosed preoperatively by fiberoptic bronchoscopic biopsy. It is difficult to distinguish pulmonary collision tumor, pulmonary mixed carcinoma and multiprimary pulmonary cancer. Primary lung cancers with more than one histological type which is not rare clinically are classified as either cancer cells that have differentiated in different directions such as adenosquamous carcinomas and combined small cell carcinomas, which is called the mixed carcinoma, or different cancers that have developed simultaneously, which is regard as the collision tumor. In the hamster model, those tumors that eventually resemble human adenosquamous carcinomas initially start as two small cancers that arise separately but concomitantly. As each separate cancer proliferates and grows, the two neoplasms encounter each other and then co-proliferate into each other as described earlier for classic'collision' tumors, which challenge the diagnosis as'adenosquamous'. The total principle of treatment is similar to the single carcinoma.We should consider the grade of malignancy and the stage of all the components, then giving a individual and multidisciplinary Combined Modality Therapy. The treatment is given priority to surgical treatment with chemotherapy, radiotherapy, traditional Chinese medicine and immune therapy. Those who is elder, in advanced stage or cannot tolerate surgery may be used the nonoperative treatment method to control the illness. The prognosis depends on the stages and the biological characteristics of all the components of collision tumor, and most scholars consider that it mainly depends on the more malignant or the advanced pathology stages of the tumorous components. The preoperative diagnosis as "shadow in the inferior lobe of right lung" was determined, with surgical indications and no absolute operative taboo. The patient receive the operation that is lower lobe resection of right lung with hilus pulmonis and mediastinum lymph nodes dissections. The pathological finding is that there are three nodules in the inferior lobe of right lung, which respectively is well-differentiated squamous cell carcinoma, moderately differentiated squamous cell carcinoma and moderately differentiated adenocarcinoma. The patient recovered well after operation and got four cycles of chemotherapy with paclitaxel plus carboplatin scheme. Follow up, there are not recurrence and metastasis.Conclusion:Pulmonary collision tumor is rare in clinic. And it is difficult to diagnose and distinguish with pulmonary mixed carcinoma and multiprimary pulmonary cancers,and on the other hand.different components of collision tumor has its own biological characteristics and TNM stages.which make it difficult to the treatment of collision tumor. Therefore, the diagnosing and reasonable choice of multidisciplinary individual treatment schemes play an important role in the prognosis of lung collision tumor.