Abdelmoneim Nancy A, Elfouly Aya M, Abou Madawi Nourhan A
Oral Pathology Department, Faculty of Dentistry, Alexandria University, Champollion Street, Azarita, Alexandria, 21521, Egypt.
Diagn Pathol. 2025 Apr 2;20(1):34. doi: 10.1186/s13000-025-01628-z.
Microsecretory adenocarcinoma (MSA) is a newly identified entity in the WHO classification of salivary gland tumors characterized by MEF2C::SS18 fusion. It was previously considered as adenocarcinoma not otherwise specified (NOS). With the discovery of new gene fusions specifying distinct salivary gland tumors and restricting the diagnosis of adenocarcinoma NOS, five cases of MSA were recognized for the first time using targeted RNA sequencing. Afterwards, further authors reported MSA in the salivary glands and more recently in the skin.
We reviewed the literature for all cases of MSA reported in English-language articles. We comprehensively discussed clinical, histopathological, immunohistochemical and molecular findings of the retrieved cases.
Forty cases were identified. Thirty cases occurred in the salivary glands and ten cases occurred in the skin. They were characterized histologically by a well circumscribed mass formed of microcysts containing basophilic secretions and enclosed in a fibromyxoid stroma. The tumor cells were flattened resembling intercalated duct cells with minimal eosinophilic cytoplasm and small oval nuclei. By immunohistochemistry, the tumor cells were positive for SOX10, S100, p63 and negative for p40, calponin and mammaglobin. However, cutaneous cases had a somewhat different immunoprofile.
MSA is a salivary gland malignancy that also has a cutaneous counterpart. Focusing on emphasising the almost consistent histopathological and immunohistochemical findings help in increasing the awareness of clinicians, surgeons and pathologists about it and at the same time lessening the need for more complicated diagnostic methods that are not readily available in all institutions. Despite the low-grade nature of this tumor, thorough management and rigorous follow up of cases are highly recommended due to occasional aggressive behaviour.
微分泌腺癌（MSA）是世界卫生组织唾液腺肿瘤分类中一个新确定的实体，其特征为MEF2C::SS18融合。它以前被认为是未另行特指的腺癌（NOS）。随着新的基因融合的发现，这些融合明确了不同的唾液腺肿瘤并限制了腺癌NOS的诊断，首次通过靶向RNA测序识别出5例MSA。此后，更多作者报道了唾液腺中的MSA，最近在皮肤中也有报道。
我们检索了英文文章中报道的所有MSA病例的文献。我们全面讨论了检索到的病例的临床、组织病理学、免疫组织化学和分子学结果。
共确定了40例。30例发生在唾液腺，10例发生在皮肤。它们在组织学上的特征是由含有嗜碱性分泌物的微囊肿形成的边界清楚的肿块，包绕在纤维黏液样基质中。肿瘤细胞扁平，类似闰管细胞，嗜酸性细胞质极少，核小而呈椭圆形。免疫组织化学显示，肿瘤细胞SOX10、S100、p63阳性，p40、钙调蛋白和乳珠蛋白阴性。然而，皮肤病例的免疫表型略有不同。
MSA是一种唾液腺恶性肿瘤，也有皮肤型。着重强调几乎一致的组织病理学和免疫组织化学结果有助于提高临床医生、外科医生和病理学家对它的认识，同时减少对所有机构都不易获得的更复杂诊断方法的需求。尽管该肿瘤恶性程度低，但由于偶尔会出现侵袭性行为，强烈建议对病例进行全面管理和严格随访。
