Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA.
Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.
Head Neck Pathol. 2021 Dec;15(4):1192-1201. doi: 10.1007/s12105-021-01331-7. Epub 2021 May 12.
Microsecretory adenocarcinoma (MSA) is a recently described salivary gland tumor with a characteristic histologic and immunophenotypic profile and recurrent MEF2C-SS18 fusions. Because only six cases of MSA have been published, its complete clinicopathologic spectrum is unclear, and its biologic behavior has not been documented. Here, we present an updated and expanded experience of 24 MSA cases. All cases of MSA were obtained from the authors' files. Immunohistochemistry for S100, SOX10, p63, p40, SMA, calponin, and mammaglobin was performed. Molecular analysis was performed by targeted RNA sequencing, SS18 break apart fluorescence in situ hybridization, and/or reverse transcriptase polymerase chain reaction for MEF2C-SS18 fusion. Clinical follow-up was obtained from medical records. A total of 24 MSA cases were collected, from 13 women and 11 men, ranging from 17 to 83 years (mean 49.5 years). The vast majority (23 of 24) arose in the oral cavity, with the palate (n = 14) and buccal mucosa (n = 6) as the most frequent subsites. Tumors showed consistent histologic features including: (1) microcystic tubules, (2) flattened intercalated duct-like cells, (3) monotonous oval hyperchromatic nuclei, (4) abundant basophilic luminal secretions, (5) fibromyxoid stroma, and (6) circumscribed borders with subtle infiltration. The tumors were very consistently positive for S100 (24 of 24), p63 (24 of 24), and SOX10 (14 of 14) and negative for p40 (0 of 21), calponin (0 of 12) and mammaglobin (0 of 16), while SMA (4 of 20) was variable. MEF2C-SS18 fusion was demonstrated in 21 of 24 cases; in the remaining 3 cases with insufficient RNA, SS18 break apart FISH was positive. Treatment information was available in 17 cases, all of which were managed with surgery only. In 14 cases with follow-up (1-216 months, mean 30), no cases recurred or metastasized. MSA is a distinct salivary gland neoplasm with remarkably consistent clinical, histologic, immunophenotypic, and genetic features that generally behaves in an indolent manner following surgery alone. These observations solidify MSA as a unique, low-grade salivary gland carcinoma that warrants inclusion in the next version of the WHO classification of head and neck tumors.
微分泌性腺癌（MSA）是一种最近描述的唾液腺肿瘤，具有特征性的组织学和免疫表型特征，以及复发性 MEF2C-SS18 融合。由于只有六例 MSA 被发表，其完整的临床病理谱尚不清楚，其生物学行为也没有被记录。在这里，我们报告了 24 例 MSA 病例的更新和扩展经验。所有 MSA 病例均来自作者的档案。进行了 S100、SOX10、p63、p40、SMA、钙调蛋白和乳球蛋白的免疫组织化学染色。通过靶向 RNA 测序、SS18 分离荧光原位杂交和/或逆转录聚合酶链反应进行 MEF2C-SS18 融合的分子分析。从病历中获得临床随访。共收集了 24 例 MSA 病例，来自 13 名女性和 11 名男性，年龄 17 至 83 岁（平均 49.5 岁）。绝大多数（24 例中的 23 例）发生在口腔，其中腭（n=14）和颊黏膜（n=6）是最常见的部位。肿瘤表现出一致的组织学特征，包括：（1）微囊性小管，（2）扁平的中间导管样细胞，（3）单调的椭圆形深染核，（4）丰富的嗜碱性腔内分泌物，（5）纤维粘液样基质，（6）边界清晰，轻微浸润。肿瘤非常一致地对 S100（24 例中的 24 例）、p63（24 例中的 24 例）和 SOX10（14 例中的 14 例）呈阳性，对 p40（21 例中的 0 例）、钙调蛋白（12 例中的 0 例）和乳球蛋白（16 例中的 0 例）呈阴性，而 SMA（20 例中的 4 例）则呈多变性。在 24 例中有 21 例显示 MEF2C-SS18 融合；在其余 3 例 RNA 不足的病例中，SS18 分离 FISH 阳性。在 17 例有治疗信息的病例中，均仅接受手术治疗。在 14 例有随访（1-216 个月，平均 30 个月）的病例中，无病例复发或转移。MSA 是一种独特的唾液腺肿瘤，具有显著一致的临床、组织学、免疫表型和遗传特征，单独手术后通常表现为惰性行为。这些观察结果使 MSA 成为一种独特的、低级别唾液腺癌，值得纳入世界卫生组织头颈部肿瘤分类的下一个版本。
