Pick a terminology and stick to it

There is more disorder than order in naming tumors:
1) a benign tumor typically ends in an -oma. Except for some malignant tumors like lymphoma, mesothelioma, meloma, glioma (and there is much more). And then there are -omas that aren't even tumors: hamartoma, tuberculoma, granuloma, etc, etc
2) Then there are the malignant tumors: which end in -carcinoma (in epithelial derived tumors) or -sarcoma (in mesoderm derived tumors). Except for the ones named after their discoverer. Also, the root of the word typically comes from the cell type, like fibroscarsoma, liposcarsoma. Oh, except for almost all of the epithelial derived tumors, which have no root convention AT ALL.

Can someone intervene please? I'm an engineer!!! Engineers don't memorize. We understand, compute...derive even!!