Departments of Pathology and Laboratory Medicine.
Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
Am J Surg Pathol. 2023 Nov 1;47(11):1219-1229. doi: 10.1097/PAS.0000000000002120. Epub 2023 Sep 9.
Multiple 3-tiered grading systems exist for mucoepidermoid carcinoma (MEC), leading to controversial results on the frequency and prognostic values of each grade. We aimed to identify prognostic histologic factors and to evaluate grading schemes in this retrospective study of 262 resected primary head and neck MECs. The rate of nodal metastasis was 8.4%. Large tumor size, tumor fibrosis, infiltrative border, lymphovascular invasion, perineural invasion, atypical mitosis, mitotic index (MI) ≥4/2 mm 2 (4/10 HPFs), necrosis, and pT4 stage were associated with increased risk of nodal metastasis. The 5-year recurrence-free survival (RFS) was 95%. Significant prognostic factors for RFS included infiltrative border, tumor-associated lymphoid stroma, architectural patterns (macrocystic, microcystic, and noncystic), anaplasia, atypical mitosis, MI, necrosis, lymphovascular invasion, margin, pT stage, and tumor size. Nuclear anaplasia, high mitotic rate, and ≥25% microcystic component were significant independent prognostic factors on multivariate survival analysis. There was no significant difference between low-grade (LG) and intermediate-grade (IG) MECs in terms of risk of nodal metastasis and outcomes using all 4 known grading systems. Rather, high-grade MEC was consistently associated with an increased risk of nodal metastasis at presentation and decreased RFS and distant metastasis-free survival (DMFS) compared with the LG/IG MECs. We therefore recommend simplifying MEC grading to a 2-tiered grading scheme using MI and/or tumor necrosis. Using a 2-tiered grading, high-grade histology independently predict RFS, and is associated with a 25% risk of nodal metastasis, a 5-year RFS of 76%, and a 5-year DMFS of 76%, whereas LG MEC has a nodal metastasis rate of 7.0%, 5-year RFS of 97% and 5-year DMFS of 99%.
存在多种用于黏液表皮样癌（MEC）的三级分级系统，导致各等级的频率和预后价值存在争议。在这项对 262 例头颈部原发性 MEC 切除标本的回顾性研究中，我们旨在确定具有预后意义的组织学因素，并评估分级方案。淋巴结转移率为 8.4%。大肿瘤大小、肿瘤纤维化、浸润性边界、淋巴血管侵犯、神经周围侵犯、非典型有丝分裂、有丝分裂指数（MI）≥4/2mm²（4/10HPFs）、坏死和 pT4 期与淋巴结转移风险增加相关。5 年无复发生存率（RFS）为 95%。RFS 的显著预后因素包括浸润性边界、肿瘤相关淋巴间质、结构模式（大囊型、小囊型和非囊型）、间变、非典型有丝分裂、MI、坏死、淋巴血管侵犯、切缘、pT 分期和肿瘤大小。核间变、高有丝分裂率和≥25%的微囊型成分是多变量生存分析的显著独立预后因素。在所有 4 种已知的分级系统中，低级别（LG）和中级别（IG）MEC 之间的淋巴结转移风险和结果均无显著差异。相反，与 LG/IG MEC 相比，高级别 MEC 在初诊时始终与淋巴结转移风险增加、RFS 和远处无复发生存率（DMFS）降低相关。因此，我们建议使用 MI 和/或肿瘤坏死简化 MEC 分级为 2 级分级方案。使用 2 级分级，高级别组织学独立预测 RFS，并且与 25%的淋巴结转移风险、5 年 RFS 为 76%和 5 年 DMFS 为 76%相关，而 LG MEC 的淋巴结转移率为 7.0%，5 年 RFS 为 97%和 5 年 DMFS 为 99%。
