Primary cutaneous extraskeletal osteosarcoma under a previous electrodessicated actinic keratosis

Area of Science:

• Oncology
• Dermatopathology
• Soft Tissue Sarcomas

Background:

• Extraskeletal osteosarcoma (ESOS) is rare, comprising ~1% of soft tissue sarcomas and ~4% of all osteosarcomas.
• Primary bone osteosarcoma is significantly more common than ESOS.
• The skin is an exceptionally rare primary site for ESOS.

Observation:

• This report details a case of extraskeletal osteosarcoma.
• The tumor's primary site was the skin.
• The tumor developed beneath a lesion previously treated by electrodessication for actinic keratosis.

Findings:

• The study identifies a rare instance of extraskeletal osteosarcoma.
• The findings highlight the skin as a potential, albeit infrequent, primary site for this sarcoma.
• The specific association with a pre-existing actinic keratosis is noted.

Implications:

• This case expands the understanding of rare tumor presentations.
• It underscores the importance of considering rare diagnoses in skin lesions, even after treatment.
• Further research into the pathogenesis of skin-based ESOS may be warranted.