Egg shell calcification seen in silicosis is due to: (A) Hilar lymphnode enlargement, (B) Pleural thickening, (C) Pulmonary edema, (D) Dilated vessels
Answer is A. (a) Hilar lymphnode enlargement > Enlargement of the hilum is common with chronic and accelerated silicosis. In about 5-10% of cases, the nodes will calcify circumferentially, producingso-called "Eggshell" calcification.> This finding is not pathognomonic (diagnostic) of silicosis. In some cases, the pulmonary nodules may also become calcified.