Thoracic splenosis

Splenosis is defined as the autotransplantation of splenic tissue, usually after splenic rupture following thoracoabdominal trauma.
It most commonly occurs in the peritoneum, omentum, and the mesentery, usually identified as nodules of splenic tissue either on imaging, necropsy or at
subsequent laparotomy. Thoracic splenosis is an uncommon phenomenon usually following thoracoabdominal trauma involving concurrent injury to the diaphragm and spleen.
In 1937 Shaw and Shafi described the first case of post-traumatic intrathoracic splenosis discovered at necropsy (1). Fewer than 20 cases have been reported in the loiterature since then.

Thoracic splenosis usually becomes evident after multiple years after the injury, as much as 6-42 years (2). They present as asymptomatic pulmonary nodules which can be multiple or solitary . All lesions however are pleural based and almost always located in the left hemithorax.

Presence of a pulmonary nodule in a patient with history of injury to the diaphragm and spleen should arouse suspicion of splenosis. Although the findings on CT scan are not diagnostic , correlation with an appropriate prior history of trauma with splenectomy , and relatively stable appearance of the pleural nodules suggests a diagnosis of thoracic splenosis. Appropriate further investigation such as nuclear scanning (99mtechnetium-labelled sulphur colloid) may prevent an unnecessary and potentially harmful operation.
Alertness to the possibility of thoracic splenosis can lead to confirmation of the
diagnosis by the use of radionuclide scanning, and so prevent unnecessary thoracotomy and rendering the patient asplenic.