You have only mentioned the PET CT finding of thorax. In PET CT scan increased uptake of the contrast signifies increased metabolic activity of that region. Now in PET scan increased uptake can be due to any granulomatous disease
, sarcoidisis etc) and malignancy. Now, always PET CT should be read with the clinical profile of the patient. You must consult a pulmonologist
because the patient need bronchoscopy
and other supportive investigations for diagnosis.