'Carcinomas' are cancers that originated from epithelial cells. Examples are legion, and include skin cancers, most lung and stomach cancers, and cervical cancer.
Sarcomas, on the other hand, are malignant neoplasms derived from mesenchymal tissue. The origin or the word comes from the ancient Greek word for 'fleshy', which is apt, since these tumours tend not to have much connective tissue stroma. Examples of sarcomas are leiomyosarcoma, osteosarcomas, and even (on most classifications), leukaemias and lymphomas.
OK, what is mesenchyme?
Mesenchyme is the embryological tissue from which all types of supporting connective tissue and vessls are derived.
And parenchyma vs stroma?
Most tissues (including cancers) have a mixture of functionally specialised cells and less specialised supporting tissue, to which the terms 'parenchyma' and 'stroma' may be applied, repectively. As noted, in cancers, it is the parenchymal element that gives the tumour its name.