Accessory spleniculi in the right hemithorax

Accessory spleniculi are present in the thoracic cavity without a history of trauma due to anomalies in the development of spleen. We report the case of a 62-year-old woman with hereditary spherocytosis and previous splenectomy with an incidental mass on a chest radiograph and an indeterminate diagnosis on needle biopsy. The probable sequence of embryological events that may explain the anatomic presence of splenic tissue in the thorax is discussed.