Department of Pathology, National Cancer Center Hospital, Tokyo, Japan.
Departments of Hematology, National Cancer Center Hospital, Tokyo, Japan.
Pathol Int. 2021 Oct;71(10):674-681. doi: 10.1111/pin.13148. Epub 2021 Aug 2.
The diagnosis of histological transformation of follicular lymphoma can be challenging and ambiguous. We investigated the distribution of the Ki-67 labeling index of histological transformation of follicular lymphoma and determined its cutoff value to predict poor outcomes. The diagnostic criteria for histological transformation were a diffuse pattern of proliferation and a proportion of large lymphoma cells ≥20%. Of the 1121 patients with follicular lymphoma, 171 (15%) showed histological transformation to diffuse large B-cell lymphoma. Of these, 76 patients, whose biopsies were obtained from the sites with the highest maximum standardized uptake values, according to the positron emission tomography findings, were included. The Ki-67 index ranged from 16.8% to 98.4% (median, 60.6%). In patients with histological transformation, the most significant differences were found in progression-free survival (p = 0.087, 58% vs. 87% at 2 years) and overall survival (p = 0.024, 53% vs. 85% at 5 years) when a 70% cutoff was used. Additionally, overall survival was significantly shorter in patients with histological transformation with maximum standardized uptake values of ≥20 (p < 0.0001) and absence of a follicular lymphoma component (p = 0.004). A Ki-67 index of ≥70% was a significant adverse factor for overall survival in patients with histological transformation of follicular lymphoma and may predict poor outcomes.
滤泡性淋巴瘤的组织学转化的诊断具有挑战性且存在歧义。我们研究了滤泡性淋巴瘤组织学转化的 Ki-67 标记指数的分布，并确定了其截断值以预测不良预后。组织学转化的诊断标准为弥漫性增殖模式和大淋巴瘤细胞比例≥20%。在 1121 例滤泡性淋巴瘤患者中，有 171 例（15%）发生弥漫性大 B 细胞淋巴瘤的组织学转化。其中，76 例患者的活检取材部位是根据正电子发射断层扫描（PET）结果，选取最大标准化摄取值最高的部位。Ki-67 指数范围为 16.8%至 98.4%（中位数为 60.6%）。在组织学转化患者中，当使用 70%的截断值时，无进展生存期（p=0.087，2 年时 58%比 87%）和总生存期（p=0.024，5 年时 53%比 85%）差异最显著。此外，当最大标准化摄取值≥20 时（p<0.0001）或缺乏滤泡性淋巴瘤成分时（p=0.004），组织学转化患者的总生存期显著缩短。Ki-67 指数≥70%是滤泡性淋巴瘤组织学转化患者总生存期的不良预后因素，可能预示不良预后。
