Multifocal kaposiform haemangioendothelioma.

Kaposiform haemangioendothelioma (KHE) is a rare, locally aggressive vascular spindle cell proliferation, with resemblance to Kaposi's sarcoma. This tumour usually occurs in skin and retroperitoneum of infants and young children and is often complicated by the Kasabach-Merritt phenomenon (KMP). A 3-year-old boy presented with a right submandibular swelling due to lymphadenopathies, a violaceous skin lesion at the left commissure of the lips and an ill-defined lesion in the right thyroid lobe. There were some signs of KMP. Histological examination revealed a typical infiltrative multilobular spindle cell proliferation with slit-like vascular spaces in these three localisations. Immunohistochemical stains showed positivity for CD34 and CD31 and many alpha-smooth muscle actin-positive spindle cells around the vascular spaces. There was no Herpes virus type 8 expression. The presented case is unique in two ways. First, thyroid involvement of KHE has never been described in the literature until now. Secondly, and most remarkably, the multifocal presentation in three anatomically distinct and separated localisations is extremely unusual.