Saccular common iliac artery aneurysm associated with HLA-A26 and HLA-B27 in a young adult patient: a surgical case report and literature review

The human leukocyte antigen (HLA) is a major histocompatibility complex antigen found in almost all human cell membranes. Half of the HLA alleles are inherited from each parent. However, little is known about the relationship between HLA and abdominal aortic aneurysms. Herein, we present a rare surgical case of a saccular common iliac artery aneurysm associated with HLA-A26 and HLA-B27 in a young adult patient, along with a literature review. A 26-year-old Japanese man presented with high fever and right lower abdominal pain. Contrast-enhanced computed tomography revealed appendicitis, a 20-mm saccular aneurysm at the origin of the left common iliac artery, and an 8-mm gastric varix. After undergoing laparoscopic appendectomy, the patient was referred to our institution for management of this rare aneurysm. His mother had a history of uveitis and ankylosing spondylitis treated with steroids, suggesting that he may have inherited HLA-B27. Endovascular aortic repair was performed using an AFX2 stent graft under general anesthesia. The patient’s postoperative course was uncomplicated, and he was discharged on postoperative day three. Postoperative HLA typing revealed HLA-A11, HLA-A26, HLA-B27, and HLA-B35 positivity. When aortic aneurysms are incidentally found in young patients, HLA typing should be considered in addition to specific antibodies for collagen diseases. Patients with a medical or family history of collagen disease–related vasculitis and specific HLA types should undergo careful cardiovascular follow-up.