A very well written execution and solid concept behind this entry, I am also a fan of medically themed RPCs and this one isn't the exception. I am quite pleased with the results, however some minor issues I feel the need to point out for the betterment of this already outstanding article:
1- Hemoptysis doesn't need to be capitalized, as it is a symptom and not a clinical entity per se.
2- As i told you before, neoplasia is an umbrella term meaning new tissue formation, used to designate cancerous tissue growth so it is kind of redundant to use neoplasia and osteosarcoma on the same sentence referring to them as different entities. My suggestion is to remove one of the terms, or just rewording it to "Continued progression of connective tissue neoplasms" since this way you cover other cancerous growths derived from connective tissue (which bone tissue is classified as).
3- The term necrosis is well used here, I would just add "extensive" before it.
Aside from these minor issues, this is an entry worth of the first 100 article spots.