Although a xanthogranuloma is a relatively common benign cutaneous condition and ossification has been observed within many cutaneous lesions, the association between ossification and xanthogranuloma has not, to our knowledge, been reported previously. We believe we describe for the first time the case of a xanthogranuloma with marked osseous metaplasia on the trunk of a 41-year-old woman. Microscopically, the lesion showed typical features of a xanthogranuloma, with the exceptional feature of exuberant bone formation. The presence of bone within this lesion is likely secondary to a metaplastic process.