Characterization of intravascular papillary endothelial hyperplasia: a multicentre cohort.

Intravascular papillary endothelial hyperplasia (IPEH) is an uncommon benign malformation of the skin and subcutaneous tissue. In this retrospective multicentre study, we aimed to investigate the clinical and pathological features of 261 patients with IPEH. IPEH is classified into three categories; in our study, the proportions were pure (50%), mixed (46%) and extravascular (4%). IPEH frequently stained positive for immunohistochemical markers such as CD31, CD34, smooth muscle actin and erythroblast transformation-specific-related gene. Clinicians' initial impression of the lesion often included ambiguous terms such as 'soft tissue mass'. There is an opportunity for increased awareness of this lesion and its consideration within a differential diagnosis.