Center of Oral Clinical Examination, Hiroshima University Hospital, Hiroshima, Japan.
Department of Oral & Maxillofacial Pathobiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Pathol Int. 2022 Jul;72(7):371-375. doi: 10.1111/pin.13236. Epub 2022 May 21.
Non-sebaceous lymphadenoma is a rare benign salivary gland tumor comprised of non-sebaceous epithelial cells and lymphoid tissue. Although its clinicopathological features have been described, its histogenesis and genetic background have not yet been elucidated. MAML2 rearrangement and the resultant CRTC1/3-MAML2 fusion gene are well-known specific genetic changes in mucoepidermoid carcinoma. Here, we present a case of lymphoepithelial tumor characterized by histomorphology of the non-sebaceous lymphadenoma and CRTC1-MAML2 fusion gene. The patient was an 83-year-old woman with an 8-year history of a solid, well-circumscribed tumor in the parotid gland. Histologically, the tumor was surrounded by thin fibrous connective tissue and was composed of tubular-cystic and solid nests of epithelial cells equally distributed in the lymphoid tissue. The histological features were suggestive of non-sebaceous lymphadenoma. Although the histomorphology was not consistent with mucoepidermoid carcinoma, a diagnosis of non-sebaceous lymphadenoma-like mucoepidermoid carcinoma was made based on the presence of the CRTC1-MAML2 fusion gene. The histological features alone could not establish the diagnosis, and ancillary molecular analysis was required.
非皮脂性淋巴腺瘤是一种罕见的良性唾液腺肿瘤，由非皮脂上皮细胞和淋巴组织组成。虽然其临床病理特征已有描述，但它的组织发生和遗传背景尚未阐明。MAML2 重排和由此产生的 CRTC1/3-MAML2 融合基因是黏液表皮样癌中众所周知的特异性遗传改变。在这里，我们报告了一例淋巴上皮瘤，其组织形态学表现为非皮脂性淋巴腺瘤和 CRTC1-MAML2 融合基因。患者为 83 岁女性，8 年前在腮腺区出现一个实性、边界清楚的肿瘤。组织学上，肿瘤被薄的纤维结缔组织环绕，由上皮细胞的管状-囊状和实性巢均匀分布在淋巴组织中组成。组织学特征提示为非皮脂性淋巴腺瘤。虽然组织形态学不符合黏液表皮样癌，但由于存在 CRTC1-MAML2 融合基因，诊断为非皮脂性淋巴腺瘤样黏液表皮样癌。仅凭组织学特征无法确诊，需要辅助分子分析。
