Primary cutaneous osteosarcoma.

A 78-year-old man had a 1-cm cutaneous nodule on his shoulder; subsequent excisional biopsy showed osteosarcoma. There was no connection to deeper structures, and no primary bone lesion was found. The tumor recurred at the same site 9 months after diagnosis and was reexcised. We believe this to be the first well-illustrated case of primary cutaneous osteosarcoma, which should now be included on the list of sarcomas that may occur in the skin.