Lymph Nodes and Lymphatic Changes

Often, thoracic lymph nodes are uniformly black in adults. Replacement of the black by paler tissue indicates an infiltrative process, either tumor or inflammation. Note the loss of black pigment in three of the nodes above the vessels and in the one below them.

The hilar and mediastinal lymph nodes are mostly replaced by confluent granulomas as shown here. The nodes remain discrete, and granulomas do not invade the capsule. Note the multinucleated giant cells of Langhans' and foreign body types. The aggregates of small blue cells are all that remains of the nodal lymphoid tissue. Most of the granulomas are cellular, but a few show some fibrosis (lower middle).

Within the lung, the lumen of a periarterial lymphatic is being encroached on by a granuloma (arrow). L = lymphatic. The elastic artery above shows medial thickening related to the hypertension.

Clinical summary Image 6

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