Doughnut sign on FDG-PET scan in a ruptured lung hydatid cyst.

A 13-year-old girl, complained of fever and cough with mucoid expectoration associated with episodes of streaky haemoptysis. Past history was not significant. On examination vital signs were normal with a pulse oximetry saturation of 98 percent. Chest examination revealed decreased breath sounds in the left mammary and infra-mammary area.