Thoracic splenosis: a case report and the importance of clinical history

Abstract

We present a case of thoracic splenosis in a 42-yr-old man with a medical history of abdominal surgery for a penetration injury with an iron bar of the left abdomen and back. He had been in good condition, but a chest radiograph taken during a regular checkup showed a multinodular left pleura-based mass. Computed tomography (CT) showed that the mass was well-enhanced and homogeneous, indicating a sclerosing hemangioma. Following its removal by video-assisted thoracoscopic surgery, the mass appeared similar to a hemangioma, with marked adhesion to the left side diaphragmatic pleura and lung parenchyma. Frozen section showed that the lesion was a solid mass consisted with abundant lymphoid cells, suggesting a low grade lymphoma. On permanent section, however, the mass was found to be composed of white pulp, red pulp, a thick capsule and trabeculae and was diagnosed as ectopic splenic tissue, or thoracic splenosis. Review of the patient's history and chest CT at admission revealed that the patient had undergone a splenectomy for the penetration injury 20 yr previously.

Keywords: Splenectomy; Splenosis; Thoracic Cavity.

Fig. 1

Chest radiograph of the patient taken during an annual checkup (A) and coronal and transverse views of contrast enhanced computed tomographic (CT) images (B, C). A diaphragm-based mass (arrow) was observed on the chest radiograph (A). The homogeneously enhanced mass (arrow) abuts the left lateral segment of the liver and stomach (B, C). No spleen was detected in the left upper abdominal cavity (B, C).

Fig. 2

Microscopic findings of the thoracic splenosis on frozen (A) and permanent (B-D) sections. Examination of the frozen section showed a thick capsule and trabeculae with abundant lymphoid tissue, but white and red pulp were indistinct (H&E stain, ×40) (A). The splenic tissue is tightly attached to the lung parenchyma without invasion (H&E stain, ×40) (B) and have normal splenic histology, with thick capsule and distinct white and red pulp (H&E stain, ×100 and ×200) (C, D).