• Purple-to-red nodule or papule, sessile or pedunculated; common on the gingiva (75% of cases [see Chapter 5]), upper lip, and buccal mucosa; there may be a history of bleeding (Fig. 6-1, A and B).

• Patients on cyclosporine after stem cell transplantation develop pyogenic granuloma–like lesions on the buccal mucosa or tongue rather than the gingiva (see Fig. 6-1, C).

• Proliferation of endothelial cells and capillaries (often dilated)—sometimes in a lobular pattern, often with overlying ulceration—and acute and chronic inflammation are seen; mitoses are not uncommon (Figs. 6-2 and 6-3).

• Some lesions may show significant reactive atypia with hyperchromatic and pleomorphic nuclei (Fig. 6-4).

• Fibrous ingress signals organization, and lesions may convert to fibromas—especially gingival lesions (Fig. 6-5).

• Edematous polypoid masses seen in patients after stem cell transplantation on cyclosporine are better diagnosed as reactive fibrovascular polyps.

• Excision is treatment of choice with recurrence in less than 5% of cases.

• Usually bluish blebs are less than 1 cm and found on the lips, tongue, or buccal mucosa, which may bleed; seen in middle-aged and older adults (Fig. 6-6, A-C).

• Bilateral ingual varices of the ventral tongue are common in older adults (see Fig. 6-6, D).

• Venous malformations are larger, often several centimeters in size, and usually are located on the tongue or lips (see Fig. 6-6, E).

• Varix: dilated, tortuous, thin-walled vessels with a thin muscular coat; valve leaflets may be present (Figs. 6-7 and 6-8); thrombi in various stages of organization often noted with high cellularity or hyalinization; Masson tumor (intravascular papillary endothelial hyperplasia) sometimes seen (Figs. 6-9 to 6-11)

• Venous malformation: proliferation of venules of varying sizes, sometimes intramuscular in location without proliferation of endothelial cells (Figs. 6-12 and 6-13)

• Arteriovenous malformations show the presence of both arterioles and arteries and veins and venules; these lesions have high flow, and biopsy may lead to a severe bleeding episode.

• Hereditary hemorrhagic telangiectasia shows the presence of numerous small capillaries and venules in the lamina propria.

• Excision, laser ablation, and sclerotherapy with ethanolamine oleate are useful treatments.

• Bluish, sometimes nodular, often vermiform, pulsatile lesion of the lower lip in adults; often mistaken for mucocele

• Normal artery with elastic lamina lies within the lamina propria with an artery diameter-to-depth ratio of less than 1.6 (Fig. 6-14).

• Trauma leads to pulsatile bleeding, and biopsy is diagnostic.

• There are four clinical presentations: (1) classic type involves the skin of lower legs in older men; (2) African endemic type is disseminated and involves viscera; (3) iatrogenic type is associated with immunosuppression (especially renal and lung transplantation); and (4) epidemic type is found in patients with HIV/AIDS and involves multiple sites, especially the skin and the mouth (this coexists with the endemic form in Africa).

• Dusky red or purple macule (early lesion), plaque, or mass (late lesion) is usually on the maxillary gingiva, palate, or tongue (Fig. 6-15); oral involvement is seen in only 2% to 5% of nonepidemic cases and in 60% to 70% of patients with HIV/AIDS.

• Worsening of Kaposi sarcoma is one of the features of patients on highly active antiretroviral therapy who develop immune reconstitution inflammatory syndrome.

• Cellular proliferation of spindle cells in small whorls or fascicles with abundant extravascular erythrocytes, hemosiderin and globular eosinophilic deposits, and some intracytoplasmic granules; mitotic activity may be noted (Figs. 6-16 and 6-17).

• Studies for endothelial markers such as CD31, CD34, FLI-1, and Kaposi sarcoma–associated herpesvirus (especially LANA-1) are positive; studies for D2-40 may also be positive.

• Spindle cell angiosarcoma and solitary fibrous tumor are negative for Kaposi sarcoma–associated herpesvirus.

• Monophasic synovial sarcoma is not a vascular tumor and is CD31 negative with ductlike structures that are cytokeratin positive.

• Patients newly diagnosed with HIV/AIDS require highly active antiretroviral therapy. Oral lesions are successfully treated with excision, laser ablation, intralesional vinblastine therapy, and radiation.

• Systemic therapy includes pegylated liposomal doxorubicin or daunorubicin.

• Reduction in immunosuppressive therapy in posttransplantation patients often leads to regression of tumors.