Pulmonary Erythema Migrans?

2 mm thickness [1] . It is a relatively specific sign for cryptogenic organizing pneumonia [1, 2] , but the differential diagnosis list should also include: bacterial pneumonia, lymphomatoid granulomatosis, Wegener’s granulomatosis, tuberculosis, mucormycosis, paracoccidioidomycosis, sarcoidosis, cancer and pulmonary infarction. Although the pathogenesis of the ‘reversed halo sign’ is not yet understood, a recent tick-bite (Ixodes ricinus) is not a recognized risk factor. Identification of this imaging feature in correlation with clinical data, medical history and laboratory investigation results serves as a useful clue for establishing an accurate diagnosis.