To demonstrate some different modalities of lung lesions in schistosomiasis mansoni, the authors relate a series of illustrative, though unusual cases, stressing the diversity of the multiple factors involved. In the present studied case, besides a definite symptomatology of paroxistic attacks of asthma, a series of radiological studies through seven years showed a pleuro-parenchymatous image characterized by irregularities of radioopacity, with extensive fibrous proliferation especially on the rightside, and marked deviation of the mediastinum also to the right; cardiac area was apparently normal. Microthoracotomy showed dominant pleural lesion enclosing the right superior lobe, affecting widely the parenchyma. Decortication of medium and right inferior lobes, partial reexpansion of their parenchyma, and pulmonary biopsy were performed. Histopathological study disclosed a predomiantly focal, but relatively extensive, and severe case of pulmonary arteritis without cor pulmonale. This pulmonary involvement occured isolated, not related to a hepato-splenic symptomatology, and consequently there was no syndrome of portal hypertension to indicate the preferentiai way of migration of the eggs, and eventually of the worms to the lungs.