The xanthogranulomatous process (XP), is a form of acute and chronic inflammation characterized by an exuberant clustering of foamy macrophages among other inflammatory cells.
[4] The xanthogranulomatous type of inflammation is most-commonly seen in pyelonephritis and cholecystitis, although it has more recently been described in an array of other locations including bronchi, lung, endometrium, vagina, fallopian tubes, ovary, testis, epididymis, stomach, colon, ileum, pancreas, bone, lymph nodes, bladder, adrenal gland, abdomen and muscle.
Cozzutto and Carbone suggested that a wide array of entities characterized by a large content of histiocytes and foamy macrophages could be traced back at least in part to a xanthogranulomatous inflammation.
Under microscope, the cellular infiltrate includes neutrophils, lymphocytes, plasma cells, erythrocytes, hemosiderin-laden macrophages and prevalent foamy histiocytes.
[20] Destructive tumor-like masses with variable extension into adjacent fat and connective tissue can occur in cases involving organs such as kidney and gallbladder.