Clear cell hidradenoma of breast:a clinicopathological analysis
LUO Jia
WU Ying-yue
ZENG Xiang-fei
YU Wen-die
PENG Heng
WEI Bing
Abstract：Objective To study the clinicopathological features,molecular genetic alterations,and differential diagnosis of clear cell hidradenoma(CCH)from mucoepidermoid carcinoma(MEC)and adenomyoepithelioma of the breast.Methods The clinicopathological data,immunohistochemistry and MAML2 gene detection were retrospectively analyzed in 3 cases of CCH.The literature review was conducted.Results The patients were all female,aged 37,48,and 45 years,respectively,who presented with palpable breast masses.Ultrasonography revealed mixed cystic-solid masses with relatively well-defined borders and regular shapes.Two cases were surgical resection specimens,while one case was diagnosed by core needle biopsy.Two cases located within the mammary parenchyma,and one case occurred in the mammary skin.Gross examination revealed nodules with cystic to solid architecture.Microscopically,the tumor exhibited lobulated solid nodules extending into dilated ducts or cysts,with uneven thickness of the fibrous capsule wall.The solid regions were predominantly composed of two types of cells arranged around a fibrovascular axis.The predominant cellular component consisted of polygonal cells with clear or eosinophilic cytoplasm,occasionally accompanied by squamous differentiation.Nuclei were round or oval with small nucleoli or deeply stained chromatin,lacking atypia and mitotic figures.Glands of varying sizes and shapes were scattered,lined by cuboidal,flat,or low columnar epithelium.Eosinophilic secretions or blue-stained mucus were observed within the lumen.The polygonal cells were diffusely positive for CK7,CK5/6,and p63,and negative for SMA,SMMHC,calponin,and SOX10.The CK7 staining of the glands was stronger than that of the polygonal cells,while p63 was negative.CK5/6 and SOX10 showed variant staining.FISH detected MAML2 gene rearrangement in two cases and atypical signals in one case.Neither of the two patients developed recurrence.Conclusion Breast CCH is a kind of skin adnexal type tumor with a favorable prognosis,potentially belonging to the MAML2-rearranged neoplasm similar to MEC.Tumor cell composition,SOX10 staining,and MAML2 gene detection are valuable for differential diagnosis.
Keywords：Clear cell hidradenomaBreast tumorClinicopathologic featuresMAML2 gene rearrangement
Publication Date：2025-06-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 708-713 )