Popcorn calcification on chest X-ray is seen in:

Ref:Harsh Mohan - Textbook of Pathology, 6th Edition.page no.503 Hamaoma is a tumour-like lesion composed of an abnormal admixture of pulmonary tissue components and is discovered incidentally as a coin-lesion in the chest-X-ray. Central carcinoid of the lung. The tumour shows a characteristic nested of cells separated by fibrovascular septa. These nests are composed of uniform cuboidal cells having granular cytoplasm. Pulmonary hamaomas are of 2 types: chondromatous and leiomyomatous. Chondromatous hamaoma is more common and usually asymptomatic. It forms a solitary, spherical mass, 2-5 cm in diameter, usually at the periphery of the lung. Typically, it shows nodules of cailage associated with fibrous and adipose tissue admixed with bronchial epithelium. Leiomyomatous hamaoma has a prominent smooth muscle component and bronchiolar structures. They are frequently multiple, 1-2 mm in diameter and are more commonly located near the pleura.