Splenosis: A Benign Phenomenon Mimicking Metastatic Cancer

Abstract

Splenosis is the benign heterotopic transplantation of splenic tissue that results from traumatic splenic rupture or splenectomy. Many clinicians are unfamiliar with this phenomenon, therefore it is often misdiagnosed and most patients undergo unnecessary invasive diagnostic procedures. We present a rare case of liver and splenic bed splenosis mimicking metastatic cancer. This is the case of a 58-year-old male with medical history of hypertension, migraine, bronchial asthma and nephrolithiasis who presented with diffuse abdominal pain, left flank pain and dark-colored urine for the past two days. He denied fever, chills, hesitancy, dribbling, or any other symptoms. Past medical history notable for splenectomy at age 5 secondary to a motor vehicle accident. Physical exam and laboratory tests were unremarkable except for hematuria on urine analysis. A non-contrast abdominopelvic CT identified a calculus at the ureterovesical junction with associated hydronephrosis. Also revealed evidence of prior splenectomy, a solid exophytic lesion at the right hepatorenal fossa measuring 1.8 cm x 2.3 cm, left upper quadrant lesion near the stomach measuring 1.8 cm x 1.5 cm, and small nodular lesion anterior to the rectum measuring 1.4 cm. Further evaluation included a colonoscopy which was essentially normal. A PET CT showed a bilobulated soft tissue density on the splenic bed and perihepatic soft tissue nodularities most likely representing splenosis. A Tc99m sulfur colloid liver-spleen scan demonstrated localized uptake by soft tissue densities localized on the splenic bed, left pelvic wall and right abdomen just below the right liver lobe compatible with active reticuloendothelial activity as it seen with post-traumatic migratory splenosis. We present a very interesting case of splenosis, which results from the auto-implantation of splenic pulp tissue usually due to trauma or following abdominal surgery. Frequency of splenosis varies according to type of injury, being more common after trauma that following elective surgical removal of the spleen. Spleen implants tend to be multiple as are seen in this patient who had spleen trauma at an early age. These are usually confined to the abdominal cavity; although there are reports of thoracic splenosis. On routine radiological studies, these lesions are usually indistinguishable from other benign or malignant lesions for which radioisotope studies are usually recommended to establish the diagnosis. Although most patients are asymptomatic, abdominal pain due to adhesion, torsion or spontaneous rupture can occur. Splenosis should be considered in all splenectomized patients; especially in presence of unexplained or asymptomatic abdominal mass. Whenever this entity is suspected, diagnosis is feasible through radioisotope scanning, avoiding the need of invasive procedures.