Twelve cases of aneurysmal fibrous histiocytoma of the skin, from 7 male and 5 female patients with an age range of 24-65 years (mean: 38.5 years), are described. Anatomical distribution ; lower limb/limb girdle (6 cases), upper limb/limb girdle (4 cases) and trunk (2 cases) . Lesional size ranged from 0.2cm to 6cm (mean: 1.5cm) . Two patients noticed rapid growth in tumor size as well as tenderness.
Histologically, prominent blood-filled spaces were obserbed in the cellular area of the lesion. The spaces lacked an endothelial lining and were surrounded by the area with prominent deposition of hemosiderin pigments, numerous siderophages, and multinucleated giant cells with hyperchromatic nuclei. In seven cases (58%), in addition to the cellular area, fibrous area was observed in the periphery of the lesion. We presumed that, in adittion to repeated minor trauma, a mechanical stress to the cellular area from adjacent fibrous area might be another factor in the formation of blood-filled spaces in aneurysmal fibrous histiocytoma.
