Document Type
Presentation
Publication Date
Fall 10-5-2026
Abstract
Pigmented lesions arising at sites of remote trauma can create diagnostic uncertainty when their clinical appearance overlaps with melanocytic neoplasms. A 64-year-old man presented with an asymptomatic 6-mm blue dermal nodule on the left fifth digit at the site of a penetrating pencil injury sustained during childhood. After remaining unchanged for decades, the lesion gradually enlarged over three years and produced mild nail plate deformity without periungual or subungual pigmentation. Cellular blue nevus, nodular melanoma, and graphite foreign-body granuloma were considered. Shave biopsy revealed a well-demarcated intradermal lesion containing abundant dark amorphous pigment and sclerosis. Higher-power examination demonstrated coarse granular black pigment with multinucleated giant cells and surrounding fibrosis, without melanocytic proliferation. These findings established the diagnosis of graphite foreign-body granuloma. The prolonged latency and recent enlargement illustrate how retained graphite may become clinically concerning many years after implantation. Because clinical features may overlap with melanoma and other pigmented tumors, remote trauma history can refine the differential diagnosis but cannot replace tissue examination. Histopathologic evaluation remains essential for definitive distinction of exogenous pigment from melanocytic proliferation.
Recommended Citation
Nguyen, Caddie; Brown,, Thomas DO; Green,, Bruce MD; and Cheung,, Wang, "Graphite Foreign-Body Granuloma Decades After Pencil Trauma: A Melanoma Mimic" (2026). DO Research Day. 13.
https://digitalcommons.lmunet.edu/doresearch/13
