A 64-year-old Caucasian man, with a long history of alcohol abuse complicated by hepatic cirrhosis and hypertensive portal gastropathy, presented with slightly painful progressive right forearm swelling. His only medication was spironolactone. He had no known allergies, no history of abnormal bleeding, and an otherwise noncontributory family and social history. A portal hepatic shunt had been inserted 9 months prior to presentation. Physical examination revealed a warm, indurated right forearm with purple-red macules extending circumferentially from the antecubital crease to the proximal wrist crease (Fig. 1), The right mid-forearm circumference was 2.5 cm greater than that on the left. The surface was irregularly studded with round, violaceous, nonblanching papules of 2-4 mm in diameter. No thrill or audible bruit was present. All pulses were intact and symmetric. He also had hepatomegaly, bilateral gynecomastia, palmar erythema, and numerous spider telangiectasias on the chest and abdomen. Ultrasonography of the area showed no clot; the swelling was entirely due to a fivefold expansion of the skin and subcutis. Two 4-mm punch biopsy specimens were obtained, one from a macule and one from a papule. Both specimens exhibited similar morphologic appearances. The superficial and mid-dermal plexus was filled with discrete lobular proliferations of endothelial-lined vascular spaces (Fig. 2). The endothelial cells were relatively uniform and large; their nuclei contained finely dispersed chromatin and inconspicuous nucleoli. Few mitotic figures were identified. There was no significant erythrocyte extravasation. Other areas assumed an epithelioid morphology, distinguished by large, plump endothelial cells that protruded into irregularly sized lumina. In these areas, an additional population of large cells had scattered cytoplasmic periodic acid-Schiff (PAS)-positive hyaline globules. These cells either surrounded the endothelial cells or merged imperceptibly with irregular vascular spaces containing delicate cytoplasmic projections. This proliferation was not confined to a strictly intravascular position, as demonstrated by extension outside the vascular basement membrane zone with PAS and reticulin stains. There were abundant mitotic figures (Fig. 3). Occasional lumina had fibrin thrombi, A scant infiltrate of mature, small lymphocytes surrounded the affected vascular spaces. The proliferating endothelial cells, as well as most of the stromal cells, were reactive with Ulex europaeus antigen-1 and antibodies directed against Factor VIII-related antigen, CD31, and CD34.
