A case of pencil core granuloma with an unusual temporal profile

The patient is a 47-year-old female with a bluish tumor resembling malignant melanoma at the macroscopic level on the medial aspect of her left big toe. The patient had crushed a pencil with this toe about 30 years previously and, since then, a bluish lesion had been present. About 15 years ago, the lesion had suddenly increased in size over the course of a few months. Subsequently, the size of the lesion had not changed noticeably. Ultrasonography, but not magnetic resonance imaging was a helpful preoperative examination to distinguish the lesion from malignant melanoma. The excised lesion contained a piece of material that resembled pencil lead and bluish mud. X-ray microanalysis of the lead-like material revealed that its composition was similar to that of pencil lead. Histologic examination showed features of foreign-body reaction, except for necrotic change and few histiocytes.