Pyogenic granuloma and nodular Kaposi's sarcoma: dermoscopic clues for the differential diagnosis

Abstract

Background/aim: Pyogenic granuloma (PG)-like nodular Kaposi's sarcoma (KS) has been previously demonstrated in several studies. However, to the best of our knowledge, no original study investigating the dermoscopic differential diagnosis of PG and KS exists in the relevant literature. In this study we aimed to identify dermoscopic findings providing useful clues to differential diagnosis between the two entities. Materials and methods: Patients with histopathologically confirmed PG or nodular KS were included in the study. Demographic, clinical, dermoscopic, and histopathological findings of the cases were retrospectively reviewed. Results: The most common finding observed in PG was red structureless areas (80.00%), followed by intersecting thick white lines (56.66%), ulceration (36.66%), and collarette scale (33.33%). The most common findings detected in nodular KS were polychromatic structures (56.66%) and red (46.66%) and white (13.33%) structureless areas, respectively. Conclusion: Intersecting thick white lines seem to be the strongest dermoscopic clue to PG. Striate surface scaling (n = 6) was a novel finding identified for PG. Here we also described a new vascular pattern (widespread vessels composing a network) for nodular KS.