Sarcoma vs Carcinoma

[kk]

I have same basic questions.

I have a problem defining what carcinoma means: a tumour originating in the epithelium, or can it also come from endothelium, or basically any tissue that derives from the embryonic ectoderm?

Same with sarcoma: any type of tumour that has the origin in the mesoderm? (e.g. A tumor of the blood cell lineage, bone marrow, are also considered sarcoma? A tumour of mesothelium is also a sarcoma?)

One more: is it true that a mesothelial cell and a mesenchymal cell has nothing to do with each other other than they both originate in the embryonic mesoderm?

tx!!