A case of unilateral dermatomal cavernous haemangiomatosis.

We report a 39-year-old man with unilateral dermatomal cavernous haemangiomatosis (UDCH). Clinically, three haemangiomas were unilaterally distributed in the C6 dermatome. Histologically, these haemangiomas were distinct from routine cavernous haemangioma in that hyperplasia of smooth muscle cells on the vascular wall was observed, and electron microscopy showed that smooth muscle cells contained myofilaments and a crystal-like structure in the endothelial cells. This is distinct from Weibel-Palade bodies, which are rod-shaped cytoplasmic organelles measuring approximately 0.1 microm in diameter with a parallel linear structure. In UDCH, the haemangiomas occur only in the skin. They are clinically and histologically similar to those of blue rubber bleb naevus syndrome (BRBNS), but in BRBNS there are multiple haemangiomas in the digestive tract and other organs. UDCH is distinct from Maffucci syndrome in that enchondromata and malignant tumours are absent. To our knowledge, this is the second case of UDCH reported in the literature.