Examination of the lungs of a 55 year old coal miner during autopsy reveals small hilar lymph nodes which are jet black in colour. The microscopic appearance of one lymph node is shown below. What is the most likely diagnosis ?

Anthracosis: It refers to the storage of carbon paicles in the lung and regional lymph nodes. These paicles accumulate in alveolar macrophages and are also transpoed to hilar and mediastinal lymph nodes, where the indigestible material is stored indefinitely within tissue macrophages. Workers who mine hard coal (anthracite) develop pulmonary fibrosis, owing to the presence of toxic/fibrogenic dusts such as silica. This type of pneumoconiosis is more properly classified as anthracosilicosis. - Hemosiderosis(choice C) represents intracellular storage of iron (hemosiderin). - The other choices are not associated with dark pigmentation in the lung.