MAST-CELLS IN ANGIOLIPOMAS AND HEMANGIOMAS OF HUMAN SKIN - ARE THEY IMPORTANT FOR ANGIOGENESIS

To characterize the potential role of mast cells (MC) in angiogenesis, this study tests the hypothesis that MC may be more abundant in angio lipomas than in classic lipomas. MC counts were compared in 13 subcuta neous angiolipomas and 15 subcutaneous classic lipomas stained with Gi emsa. Angiolipomas had ten times as many MC as did classic lipomas (25 .34 +/- 2.83 versus 2.41 +/- 0.37 per mm2, mean +/- SE). To clarify wh ether this difference was primary (angiogenic activity) or secondary t o the increased vascularity, MC were counted in 8 longstanding cutaneo us capillary hemangiomas versus 13 cutaneous capillary hemangiomas of recent onset (pyogenic granulomas). If MC were mediating primary angio genesis, one would expect them to be present in greater numbers in ear ly than in late hemangiomas. To the contrary, however, long-standing h emangiomas were found to have significantly more MC than had those of recent onset (52.48 +/- 14.99 versus 6.59 +/- 3.37 per mm2, mean +/- S E). These results suggest that MC may not play an essential, early rol e in the proliferation of blood vessels in angiolipomas and hemangioma s, but rather may be related to maturation of blood vessels in these t umors.