DNA flow cytometric and immunohistochemical analysis of proliferative activity in spindle cell haemangioendothelioma

Although spindle cell haemangioendothelioma was initially described as a low-grade angiosarcoma, recent reports have suggested that it is a reactive or benign vascular proliferation. In order to assess the proliferative activity in spindle cell haemangioendothelioma, 12 cases, one of which was associated with Maffucci's syndrome, were immunohistochemically analysed with antibodies against proliferating cell nuclear antigen (PCNA), Ki-67 and p53. DNA flow cytometry was performed on six of the 12 cases. Seven of the 12 patients had multiple nodules or papules. Although two cases recurred once and twice, respectively, after surgery, there was no evidence of metastasis. Immunohistochemically, the percentages of PCNA, Ki-67 and p53 positive tumour cells ranged from 0.1% to 6.4% (mean 3.3%), 0.1% to 14.9% (3.5%) and 0.1% to 2.8% (1.1%), respectively, indicating a low proliferative activity and a low p53 expression in this tumour. All seven lesions from the six cases examined flow cytometrically were DNA diploid with proliferative indices (S + G2/M-phase fractions) ranging from 4.9% to 19.5% (mean, 10.9%). These findings are compatible with a bland-looking histological picture and an indolent clinical course of spindle cell haemangioendothelioma.