Collaborative Stage

Note 1: Grade coded in this field describes whether the melanoma arises from a pre-existing lesion (primary acquired melanosis, PAM) or appears "de novo", without any pre-existing lesion. This is not the same as the histologic grade defined in the ICD-O, designating degrees of differentiation from normal tissue such as "well differentiated" or "poorly differentiated", which is coded in the traditional grade field.
Note 2: Tumors of Grade 0, Primary acquired melanosis without cellular atypia, and Grade 1, Conjunctival nevus, are not reportable to the cancer registry. Tumors of Grade 2, Primary acquired melanosis with cellular atypia (epithelial disease only) are reportable and are coded as 8741/2, per MP/H rules revision scheduled for 2010.
Note 3: Code this field only from a statement of grade describing PAM with atypia or de novo melanoma, documented by the managing physician or the pathologist in the record. Do not interpret or attempt to assign grade based on the histologic diagnosis of the tumor.

Code	Description
020	Grade 2 Primary acquired melanosis with cellular atypia (epithelial disease only) Confined to epithelium
030	Grade 3 Primary acquired melanosis with epithelial cellular atypia and invasive melanoma
040	Grade 4 De novo malignant melanoma
888	OBSOLETE DATA CONVERTED V0200 See code 988 Not applicable
988	Not applicable: Information not collected for this case (May include cases converted from code 888 used in CSv1 for "Not applicable" or when the item was not collected. If this item is required to derive T, N, M, or any stage, use of code 988 may result in an error.)
999	Grade X Unknown, not stated Information not documented in patient record

CS Site-Specific Factor 3
Grade - Melanoma Origin