Primary cutaneous osteosarcoma of the scalp: a case report and review of the literature.

We report on an 84-year-old man with a solitary, nodular lesion on the scalp. The patient had been previously submitted to electrodessications of the scalp due to multiple solar keratoses. Histopathologically, the lesion showed features of a high-grade conventional osteoblastic osteosarcoma involving the dermis. Computed tomography showed no involvement of the underlying bone tissues. Clinical examination and extensive total body radiologic workup revealed absence of bone lesions in any body site, thus suggesting a final diagnosis of primary cutaneous extraskeletal osteosarcoma. The clinico-pathological features of the case are discussed in light of the rare cases previously described in the literature.