A 13 day-old girl presented with a solitary, congenital, firm, violaceous 3 cm x 3 cm skin mass of the right lower leg. She was otherwise in good health. Her complete blood count (CBC) and coagulation studies, including PT and PTT, were all in normal range. A diagnostic biopsy was performed, which showed the tumor to consist of multiple dermal nodules of spindled and round cells, in areas forming capillary-sized and "slit-like" vascular channels. The tumor nodules were in part surrounded by hyalinized collagen. The neoplastic cells were small and relatively uniform but slightly hyperchromatic. Mitotic activity was very low and necrosis was absent. Focally the neoplastic cells formed small "glomeruloid" structures, within which could be seen minute platelet aggregates.
The neoplastic cells were CD31, CD34, and FLI1 positive but negative for GLUT1 and HHV-8.
Ramin Zargham, M.D., Ph.D.
Resident, Anatomic and Clinical Pathology
Andrew Folpe, M.D.
Consultant, Division of Anatomic Pathology
Professor of Laboratory Medicine and Pathology,
Mayo Clinic College of Medicine