[Intrathoracic splenosis. Apropos of a case].

The authors report an exceptional case of intrathoracic splenosis in a 34 year old woman suffering from a circulation injury with rupture of the spleen and left diaphragm and hemothorax. She had been splenectomized. Eleven years later, a systematic thoracic X-ray examination revealed a rounded opacity of the left extremity. Exeresis of a lump the size of a nut located in the pleural space without individualized vascular pedicle was performed. The lesion showed macroscopic and microscopic characteristics of splenic tissue. If peritoneal splenosis is more frequent, intrathoracic splenosis is exceptional (only 7 observations known). Every time, a traumatic splenic antecedent has been noted. The etiopathogeny consists of an autograft of splenic tissue most often in the pleural cavity, when a diaphragmatic lesion has been associated to the injury. The lesion is asymptomatic and does not provoke complication in that area. Histologically, the splenic parenchyma can be normal or limited to the red pulp with a more or less important degree of white pulp. The histological differences with the normal or accessory spleen are the non contractile collagenous texture of the capsular and the septa and the absence of hila. One should consider this etiology when antecedents of splenic and diaphragmatic traumatism are noted. Hepato-splenic scintigraphy can be useful in the diagnosis and help to avoid thoracotomy.