Pneumonic-type mucinous lung adenocarcinoma diagnosed by transbronchial cryobiopsy

Primary lung adenocarcinoma with lepidic growth can mimic diffuse pulmonary parenchymal processes like infectious pneumonia or idiopathic inflammatory pneumonitis. We report a case of subacute pneumonitis refractory to antibiotic therapy and empirical corticosteroids, proven to be diffuse mucinous adenocarcinoma with lepidic growth on transbronchial cryobiopsy.