The initial focal lesion of primary tuberculosis in the lung is known as

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In primary tuberculosis, the first lesion in the lung is a small subpleural granulomatous area called the Ghon focus. This represents the initial site where inhaled Mycobacterium tuberculosis is walled off by macrophages and forms a granulomatous inflammatory response. If nearby hilar lymph nodes also become involved, the lesion plus nodal involvement make up the Ghon complex. As healing occurs, calcification can cement both the focus and the nodes, producing the Ranke complex. The term caseating granuloma describes the necrotizing center often seen in TB granulomas, but it’s a histologic description, not the name of the initial lesion. So the initial focal lesion is the Ghon focus.