Colored Pencil-Core Granuloma With a Long Incubation Period After Penetration: A Case Report.

Pencil-core granulomas grow rapidly after a long incubation period, typically taking years to decades after penetration by the pencil core. However, colored pencil-core granulomas, which have different core components, have been reported to form just a few days after the core has pierced the skin. It is understood that this difference in incubation period is due to differences in reactivity to different types of foreign bodies. However, we report a rare case of colored pencil-core granuloma that took a three-month incubation period despite being caused by a green pencil-core.