FDG PET/CT findings of a ruptured pulmonary hydatid cyst with histopathological correlation.

We present a case of ruptured pulmonary hydatid cyst in a patient with hemoptysis and suspected pulmonary malignancy, for which the (18)F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) findings of absent metabolic activity within the cyst and hypermetabolism within a pericystic region of parenchymal consolidation were clues to the diagnosis. Our report is the first to correlate PET/CT findings in a ruptured cyst with histopathology. Moreover, this case demonstrates that even in nonendemic regions, ruptured pulmonary hydatid cyst should be considered in the differential for pulmonary malignancy. The ability of PET/CT to distinguish cyst rupture has implications for surgical management.