It's from coding clinic april, 1992
Lymphomas are systemic diseases that do not "metastasize" in the same way that solid tumors do (classified to categories 140--199). A lymphoma, regardless of the number of sites involved, is not considered metastatic, and should be coded to the 200--202 categories. Solid tumors frequently metastasize to the lymph nodes and/or bone marrow. These are not lymphomas; they are secondary sites of the solid tumor. In cases of solid tumor metastases to the lymphatic system, a code from category 196, Secondary and unspecified malignant neoplasm of lymph nodes; code 197.8, Secondary and unspecified malignant neoplasm of spleen; or code 198.5, Secondary and unspecified malignant neoplasm of bone marrow, should be used. Lymphomas are specifically excluded from these categories. Codes 197.8 and 198.5 and codes from category 196 should never be used for lymphomas.