[Primary pulmonary schwannoma: clinical analysis of 7 cases and review of the literature].

Objective: To analyze the clinical and radiological manifestations of primary pulmonary schwannoma in order to improve the diagnosis of this rare disease.
Methods: Seven cases of primary pulmonary schwannoma which was confirmed by pathology of surgical specimens were retrospectively analyzed.
Results: Three cases were benign (1 of pulmonary parenchymal origin and 2 of bronchial origin) and 4 were malignant (3 of pulmonary parenchymal origin and 1 of bronchial origin). There were four male and three female patients, age ranging from 31 to 74 years. All the 7 cases had chest X-ray films and 6 cases had chest CT examinations. The major complains included slight hemoptysis, cough, fever, chest pain and shortness of breath. Bronchoscopy showed bronchial tumors in 3 cases and partial stenosis of bronchus in 2 cases. Radiology showed nodules in the left main bronchus in 2 cases. Solitary mass was found in 4 cases and multiple masses (2 lesions) were found in one patient. The margin of the lesions was smooth in 3 cases (one malignant and two benign) and irregular in another three cases (all malignant). Chest CT showed reticular enhancement in one case (benign), heterogeneous enhancement in 4 cases (3 malignant and 1 benign), and peripheral enhancement with a large central hypodense area in one case (malignant). Compression of the trachea and ribs was prominent in 2 patients. Pleural effusion and blood vessel infiltration were evident in 3 patients with malignant schwannoma.
Conclusion: Primary pulmonary schwannoma is rare. The symptoms and CT manifestations are nonspecific. The size and the density of the tumor are not helpful in differentiating malignant schwannoma from the benign one. Marginal irregularity and invasion of adjacent structures are suggestive of malignancy.