Miliary tuberculosis of the lungs - Fragment of the lungs, dense consistency, dark burgundy color. The pleura is preserved, on the surface of the section there are multiple, diffusely located lesions (tuberculomas), white-gray, 2*3 mm in size. The foci of damage resemble millet grain.

On closer inspection, the granulomas have areas of caseous necrosis. This pattern of multiple caseating granulomas primarily in the upper lobes is most characteristic of secondary (reactivation) tuberculosis. However, fungal granulomas (histoplasmosis, cryptococcosis, coccidioidomycosis) can mimic this pattern as well.

Microscopically, multiple granulomas or tubercles are found in the lung tissue, the bulk of which are epithelioid cells. Among them, there are one or two giant multinucleated cells of Pirogov-Langhans with a characteristic arrangement of nuclei in the form of a crescent along the periphery of the cell. In the peripheral parts of the tubercle, a cluster of lymphocytes with a small amountof plasma cells is found. In the center of some tubercles, foci of caseous necrosis are found. Individual tubercles merge with each other, forming conglomerates of various sizes and shapes.