We read with great interest the case report by Cariati et al. [1] about an acute symptomatic type IV thoracoabdominal aortic aneurysm with supra-anastomotic aneurysm formation involving the renal and visceral arteries and including a pseudoaneurysmatic sac localized in the left psoas muscle. The authors performed endovascular treatment using a two-by-two chimney-and-periscope technique. This case is unique because it presents the first case of two-by-two chimney-and-periscope treatment of symptomatic type IV thoracoabdominal aortic aneurysm and the third case of “total visceral and renal artery endo-branching” as the authors termed. We assume that the huge pseudoaneursymatic sac formation from fusiform aortic aneurysm, as shown in Fig. 1 in the article, is another point to be underscored in this patient [1]. A saccular pseudoaneurysm with a maximum diameter of 8 cm arising from the proximal anastomosis of a previously inserted aorto-biiliac surgical prosthetic graft was presented [1]. The most frequently encountered type of abdominal aortic aneurysm is fusiform, whereas saccular aneurysm is comparatively rare [2]. A saccular pseudoaneurysm originating from a fusiform aneurysm, as in the authors’ case, is an extremely rare pathology. We aim to discuss this uncommon pathology, that is, saccular pseudoaneurysm originating from fusiform AAA, and include two additional cases of our own experience.