Thoracic splenosis of the left lung and upper abdominal area was described. Left minithoracotomy was performed due to unclear results from a fine needle biopsy and following the suggestion to obtain a tissue sample. Clinical findings were similar to neoplasmatic disease; intraoperative extension of the disease was larger than CT view and correlated with postoperative assessment with (99m)Tc sulphur colloid. This confirmed the usefulness of scintigraphic assessment in preoperative diagnosis in order to avoid thoracotomy in such cases.