File:IPLab6TB1.jpg|This is a photograph of a section of lung with an apical lesion. This lesion represents an old healed lesion from Mycobacterium tuberculosis infection. File:IPLab6TB2.jpg|This is a low-power photomicrograph of lung tissue with multiple circumscribed nodules - granulomas (arrows). File:IPLab6TB3.jpg|This is a higher-power photomicrograph of a TB granuloma. Note the eosinophilic material in the center of this granuloma (caseous necrosis) and the epithelioid macrophages and giant cells around the periphery. File:IPLab6TB4.jpg|This is a higher-power photomicrograph of a TB granuloma. The area of caseous necrosis is on the left side of the image, there are multinucleated giant cells and epithelioid macrophages throughout the remainder of the tissue. File:IPLab6TB5.jpg|High-power photomicrograph of a TB granuloma with multinucleated giant cells adjacent to an area of caseous necrosis (to the left).File:IPLab6TB6.jpg|This is a high-power (oil immersion) photomicrograph of granuloma stained with an acid-fast stain. Mycobacterium tuberculosis bacilli stain red.