The presence of an accessory spleen is considered a normal anatomic variant that occurs in 10% of the population. Accessory spleens are usually solitary and are most commonly (80%) found in the splenic hilum, but can also be located along the splenic vessels, in the bowel mesentery, in the pancreas, in the jejunal bowel wall, or in the pelvis.
Accessory spleens are most often first suspected as an incidental finding on an abdominal computed tomography scan obtained for other reasons. The presence can also be suspected if the expected characteristic blood cell morphological changes (e.g., Howell-Jolly bodies) do not appear after splenectomy.
Although not diagnostic, accessory spleens have a characteristic appearance on computed tomography and ultrasound. Findings include a round or oval-shaped lesions with distinct, sharp borders and a homogenous sonographic profile.
Although fine-needle biospsy has been described to obtain tissue for a histologic diagnosis, most authors recommend a stategy utilizing radionuclide tests to delineate the diagnosis.
Technetium Tc 99m sulfur colloid is preferentially taken up by reticuloendothelial tissue found in splenic tissue. After injection, SPECT scanning combined with use of a gamma-ray scintillation camera can combine both physiological function and anatomic location data to confirm if the unknown mass is likely aberrant splenic tissue or a mass of some other etiology.
Leave a Reply