Unusual polyp-like structures in lobular panniculitis of a patient with Behçet's disease.

Unusual histopathologic structures were observed in lobular panniculitis of a patient with Behçet's disease. These were polyp-like in shape and protruded into cavities made of lysed fat cells. Various stages of development were observed. To determine the origin of cells making up these structures, we applied various histochemical and immunohistochemical techniques and found the cells to be histiocytes (macrophages) engaged in phagocytizing degenerated fat cells and cell membranes which had formed into membranocystic lesions.