Compound Morphology Diagnoses
Rule J.Change the order of word roots in a compound term if the term is not listed in ICD-O.
Some tumors have more than one histologic pattern. The most common combinations have been listed in ICD-O, for example "mixed adenocarcinoma and squamous cell carcinoma" (M-8560/3), "papillary and follicular adenocarcinoma" (M-8340/3), and "mixed basal-squamous cell carcinoma" (M-8049/3).
The compound term "fibromyxosarcoma" is listed in ICD-O with its code M8811/3, but "myxofibrosarcoma" does not appear. "Myxofibrosarcoma" is the same as "fibromyxosarcoma," except that the word roots have been inverted, and it should therefore also be coded M-8811/3. It was impossible to list all the combinations and permutations of such compound terms. The coder must check various permutations of the word roots in a compound term if the version sought is not listed in ICD-O.