Two Cancers Arising from Different Mesenchymal Origins: An Unexpected Connection over Time and Space

摘要

Sarcomas are rare tumours, accounting for 1% of all malignancies. They are histologically diverse, presenting with more than 50 different subtypes. Sarcoma can be broadly divided into two categories—soft tissue sarcoma and bone sarcoma. Extraskeletal osteosarcoma is a unique subtype which is histologically similar to bone osteosarcoma but resides within soft tissue and has no attachments to bone. We present a rare case of a patient who initially presented with an extraskeletal osteosarcoma that was complicated by a chronic chest wall sinus and lymphedema of the left arm. He later developed enlarging left chest wall nodules at the same region that were proven to be dedifferentiated liposarcoma on biopsy 20 years later. We examine the occurrence of both extremely rare diseases of differing pathologies over the same site but separated by an extraordinarily long interval, and possible new associations to account for this phenomenon.