Cutaneous osteomas: a clinical and histopathologic review.

In 20 000 consecutive skin biopsies we found 35 cutaneous osteomas. Ten were primary while 25 appeared secondary to another abnormality. Associated with ossification were Malherbe's calcifying epithelioma, basal cell carcinoma, nevus cell nevus, appendageal and fibrous proliferations, inflammation, trauma, and calcification. Cutaneous bone formation appears to be either a hamartomatous or metaplastic phenomenon.