Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan; Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan.
Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan.
Hum Pathol. 2017 Dec;70:55-61. doi: 10.1016/j.humpath.2017.10.004. Epub 2017 Oct 24.
Hidradenoma usually presents as a solitary, slow-growing, and solid or cystic nodular lesion, which arises in various anatomical sites. Its diagnosis is occasionally difficult because the tumor shares histological features with other cutaneous appendage tumors. Recently, CRTC1-MAML2 fusion gene was reported in hidradenomas, with the fusion transcript being demonstrated in approximately 50% of cases. However, limited information is available regarding its clinical significance. Here, we investigated the relationship between the fusion gene and clinicohistopathological features. We reviewed 39 cases histologically diagnosed as hidradenoma. Reverse-transcription polymerase chain reaction (RT-PCR) was performed for all 39 cases, and fluorescence in situ hybridization was also performed for the RT-PCR-negative cases. The 39 tumors included 36 clear cell hidradenomas and 3 poroid hidradenomas. The details of the cellular components were as follows: clear cell-dominant type, 9 cases; polygonal cell-dominant type, 21 cases; and equally mixed type, 9 cases. There were no tumors with apparent mucinous cells. There were 8 tumors with prominent cystic change, 2 of which presented apocrine-like decapitated secretion. CRTC1-MAML2 fusion was detected in 10 of the 39 tumors (26%) and CRTC3-MAML2 fusion in 2 of the 39 (5%) by RT-PCR. MAML2 gene rearrangement was detected in 11 of 27 fusion gene-negative cases by fluorescence in situ hybridization. Moreover, neither the fusion genes nor gene rearrangement was detected in prominent cystic tumors and poroid hidradenomas. We conclude that CRTC1/3-MAML2 fusion gene analysis can be a useful method for diagnosing hidradenoma. Considering the histological and genetic similarity to mucoepidermoid carcinoma, hidradenoma may be a cutaneous counterpart of salivary gland mucoepidermoid carcinoma.
汗管瘤通常表现为单发、生长缓慢、实性或囊性结节性病变，可发生于各种解剖部位。由于肿瘤具有与其他皮肤附属器肿瘤相似的组织学特征，因此其诊断偶尔较为困难。最近，在汗管瘤中报道了 CRTC1-MAML2 融合基因，约 50%的病例中存在融合转录本。然而，关于其临床意义的信息有限。在这里，我们研究了融合基因与临床病理特征之间的关系。我们回顾了 39 例经组织学诊断为汗管瘤的病例。对所有 39 例进行逆转录聚合酶链反应（RT-PCR），对 RT-PCR 阴性病例进行荧光原位杂交。39 例肿瘤包括 36 例透明细胞汗管瘤和 3 例 Poroid 汗管瘤。细胞成分的详细信息如下：透明细胞占优势型 9 例，多边形细胞占优势型 21 例，混合性均占优势型 9 例。无明显黏液细胞的肿瘤。有 8 例肿瘤伴有明显囊性变，其中 2 例呈大汗腺样断头分泌。通过 RT-PCR，在 39 例肿瘤中有 10 例（26%）检测到 CRTC1-MAML2 融合，39 例中有 2 例（5%）检测到 CRTC3-MAML2 融合。荧光原位杂交检测到 27 例融合基因阴性病例中有 11 例存在 MAML2 基因重排。此外，在明显囊性肿瘤和 Poroid 汗管瘤中均未检测到融合基因和基因重排。我们得出结论，CRTC1/3-MAML2 融合基因分析可以作为诊断汗管瘤的有用方法。考虑到与黏液表皮样癌的组织学和遗传相似性，汗管瘤可能是唾液腺黏液表皮样癌的皮肤对应物。
