PECAM1 and histiocytic sarcoma: Immunofluorescence analysis revealed that, at the dermal level, HS lesions had a significantly greater quantity of CD3+ (324.29 ± 139.28 vs 14.93 ± 16.32, P < .0001) and CD31+ (322.15 ± 155.46 vs 2.84 ± 5.56, P < .0001) cells/mm2 than NS samples.