Introduction:
Rasmussen’s aneurysm is an inflammatory pseudoaneurysmal dilatation of a branch of the pulmonary artery adjacent to the tuberculous cavity. It often presents with hemoptysis resulting from its rupture. Massive hemoptysis seen in giant aneurysms is a rare but life-threatening complication of cavitary tuberculosis.

Aim:
In this case, we aimed to present a case of giant rasmussen aneurysm that did not bleed and was diagnosed incidentally.

Case study:
In this article, we present a female patient who was surprisingly diagnosed with Rasmussen’s aneurysm during her follow-up after having been admitted to our emergency department due to diabetic ketoacidosis, fever, and shortness of breath and not responding to tuberculosis treatment. She was diagnosed using multi-detector computed tomography angiography and underwent embolization with a percutaneous thrombin injection. On the day after the procedure, thoracotomy had to be performed because the pseudoaneurysm continued to show contrast enhancement on imaging. She was successfully treated with surgery.

Results and discussion:
Although pulmonary artery aneurysms are rare, it should be kept in mind that they may be related to tuberculosis. Pulmonary artery aneurysms are large asymptomatic and can reach gigantic dimensions as in this case. Rupture of an aneurysm of this size can be predicted to be mortal. Percutaneous thrombin injection can be used for treatment. However, percutaneous treatment may recur in large aneurysms, in which case surgical treatment is curative.

Conclusions:
Rasmussen aneurysm is very rare, and when it is asymptomatic, its diagnosis may be delayed until it reaches gigantic dimensions. Contrast-enhanced thorax computed tomography and especially multi-detector computed tomography angiography are helpful in diagnosis.