An asymptomatic giant AB thymoma in a patient with Down syndrome: a case report.

Background: Mediastinal mass management may represent a real challenge for all the physicians who deal with it. Mediastinum, in fact, contains different vital structures which are often involved by growing neoplasms with increasing severity. Therefore, up to 60% of the patients with mediastinal mass are symptomatic, according to the structure involved. Different neoplasms may arise essentially from all mediastinal organs, whereas thymic epithelial tumors and lymphomas represent more than 90% of mediastinal tumors.

Case description: We report the first case described of a giant asymptomatic mediastinal mass in a 43-year-old male affected by Down syndrome (DS), turned out to be a thymoma, treated exclusively and successfully with radical surgery. Despite the absence of any symptoms, the giant thymoma infiltrated the diaphragm, the pericardium, the upper lobe of the left lung together with the left phrenic nerve resulting in the compression of heart and great vessels.

Conclusions: To date, this is the first description of a thymic malignancy in a patient with DS, that usually is characterized by a low-incidence of solid tumor except for germ-cells ones. Surgery has been extremely challenging, due the clinical condition of the patient together with the tumor features; nevertheless, oncological radicality criteria were completely fulfilled. After four years from surgery, the patient is alive and still disease-free, highlighting the importance of radical surgery.