Blizzard Sign as a specific endobronchial ultrasound image for ground glass opacity: A case report

We report a case of lung adenocarcinoma presenting as pure ground glass opacity (GGO) and diagnosed by bronchoscopy with the use endobronchial ultrasound with a guide sheath (EBUS-GS). The lesion was indistinguishable by real-time fluoroscopy but simultaneous endobronchial ultrasound scanning of the involved lung segment showed a hyperechoic shadow that was subtly more intense than a typical snowstorm appearance when scanning normal alveolar tissue. Transbronchial biopsy from this area revealed adenocarcinoma with lepidic growth. On hindsight, it was the aforementioned ultrasound pattern that helped us decide the sampling site for EBUS-GS guided TBB when fluoroscopy was equivocal. We hypothesize that this pattern is specific for GGO and we name it the Blizzard Sign.