When the diagnosis is a zebra: pulmonary artery aneurysm.

Some ailments maypresent so distinctively that the diagnosis is often unquestionable. Other cases, however, may present typically, but have atypical findings. We describe a case of a patient who presented to our institution with recurrent hemoptysis. The clinical features were suggestive of an underlying infection or malignancy. When these were ruled out, the search for a zebra had begun. The patient underwent sixty four-slice computerizedtomographic angiography (CTA) which revealed a right pulmonary artery aneurysm (PAA). Timely involvement of interventional radiologists and thoracic surgeons prevented a potentiallylife-threatenninghemorrhage. This case underlines the importance of awareness of this condition in the formulation of a differential diagnosis forhemoptysis. PAAis a rare condition that is either congenital or acquired. Common acquired etiologies include chronic thromboembolic pulmonary hypertension, infections (syphilis and tuberculosis), vasculitis (Behcet's and Hughes-Stovin syndromes), neoplasms (primaryandmetastatic), andtrauma(most often iatrogenic).