Microscopic examination revealed a circumscribed, dermal-based vascular tumor that extended focally into the subcutaneous fat. The lesion showed an admixture of smaller-caliber thick-walled vessels, larger cavernous vessels, and proliferating spindled cells. In areas of small vessels, the endothelial lining appeared somewhat plump, with hyperchromatic nuclei and minimal cytoplasm. Some of the larger vessels contained fibrin thrombi. Mitotic activity was inconspicuous. A Warthin-Starry stain was negative for bacteria. The results of a human herpesvirus 8 stain were also negative.
Multiple Violaceous Nodules in a 46-Year-Old Man—Diagnosis. Arch Dermatol. 2006;142(5):641-646. doi:10.1001/archderm.142.5.641-e