A hallmark feature of caseous necrosis is:

Caseous necrosis is characterized by a distinctive cheese-like gross appearance due to the combination of dead cell debris and lipid material. This hallmark feature is commonly seen in granulomatous inflammation associated with tuberculosis. The affected tissue appears soft, white, and friable, resembling clumpy, cottage cheese. Unlike liquefactive necrosis, where the tissue is completely digested, caseous necrosis maintains a firm, amorphous structure. Recognizing this appearance is crucial during surgical biopsy and pathological examination for accurate diagnosis.

Reference: Robbins Basic Pathology, Kumar, Abbas, Aster, 10th Edition.