A rare low-grade angiosarcoma. First six cases of these vascular tumours in children were described and designated as "malignant endovascular papillary angioendothelioma" by Maria Dabska in 1969 and since then often called "Dabska tumours." Most often they primarily affects the skin of children and have a distinctive histological pattern of wide, anastomosing vascular channels with intravascular papillary outpouchings projecting, sometimes, in a glomerulus-like pattern, into a lumen lined by atypical columnar endothelial cells.
Dilated thin walled intradermal vessels ("lymphangioma-like") containing cellular papillary structures of endothelial cells and lymphocytes. Endothelial cells are small with small portions of eosinophilic cytoplasm and hobnail nuclei with cytologic atypia. Papillary tufts may have hyaline core with lymphocytes clustering around. The papillary endothelial proliferation with a central hyaline core is one of the most characteristic features of endovascular papillary angioendothelioma; however, this type of proliferation has been observed in other vascular tumours, such as angiosarcoma, retiform hemangioendothelioma and glomeruloid haemangioma.
It was termed malignant because of its mitotic activity, areas of necrosis, and demonstrated ability to metastasize to regional lymph nodes. Despite these features it had a uniformly good prognosis. The histological diagnosis of this entity is controversial although the tumour is included in the World Health Organization classification. With respect to their histological appearance and their biological behaviour these tumours are intermediate between benign haemangiomas and malignant angiosarcomas. There are four recognised subgroups of these tumours: the epithelioid hemangioendothelioma, a spindle cell variant, kaposiform hemangioendothelioma and malignant endovascular papillary angioendothelioma, also known as a Dabska tumour.
This description was submitted by Krzysztof W. Zielinski.
- M. Dabska:
Malignant endovascular papillary angioendothelioma of the skin in childhood. Clinicopathologic study of 6 cases. Cancer, September 1969, 24 (3): 503-510.