Fig. 4From: Giant insulinoma: report of a case and review of published reportsWell-differentiated tumor cells were observed in most parts of the tumor (a); however, poorly differentiated tumor cells were identified in a small proportion of it (b). The Ki67 index was 2–5% in most of the tumor (c); however, the poorly differentiated area had a Ki67 of over 20% (d)Back to article page