A 37 years-old white man, smoker, was interned for having dry cough and pain in the left hemithorax (HE). The exam has show diminished vesicle mumble in the medium third part of the HE. The thorax computer tomography showed expansive nodular lesion of the 7 degrees coster arch projecting within the HE, with density of the bulk part and discreet enhance by the contrast. Imuno-histochemistry was compatible to benign schwannoma. We consider the intercostal benign schwannoma diagnosis must be taken before all the posterior or lateral intrathoracic mass that follows with small syntomathology and absence of clinical manifestation of malignity.