diffuse alveolar septal amyloidosis with wildtype transthyretin with spontaneous lung hematoma we experienced a mass formation in the right lower lobe in a patient with cardiac amyloidosis and heart failure radiologic findings of the chest showed no abnormality except a mass the patient had nonvalvular atrial fibrillation and was taking edoxaban surgical resection of the mass revealed a hematoma further pathologic evaluation revealed diffuse alveolar septal amyloidosis with transthyretin attr the genetic testing found no mutation in the ttr gene therefore systemic wildtype ttr amyloidosis attrwt was confirmed alveolar septal attrwt is rare and patient had alveolar septal attrwt with spontaneous lung hematoma