title: Immunohistochemical expression of myoepithelial markers in adenomyoepithelioma of the breast: a unique paradoxical staining pattern of high-molecular weight cytokeratins.
abstract: To determine which immunohistochemical markers are useful for the identification of neoplastic myoepithelial cells in adenomyoepithelioma of the breast, the expression of seven myoepithelial markers (α-smooth muscle actin (α-SMA), calponin, p63, CD10, cytokeratin 5/6, cytokeratin 14, and S-100) was examined in 19 lesions from 16 patients. The lesion consisted of seven spindle and 12 clear cell lesions. For normal myoepithelial cells, α-SMA, calponin, and p63 were significantly more sensitive than cytokeratin 5/6, cytokeratin 14, and S-100. There was no significant difference in the expression of α-SMA, calponin, p63, and CD10 in neoplastic myoepithelial cells of adenomyoepithelioma regardless of spindle or clear cell types. In spindle cell lesions, high-molecular weight cytokeratins (HMWCK; cytokeratin 5/6 and cytokeratin 14) tended to show higher staining scores and S-100 showed lower staining scores than other markers. In clear cell lesions, HMWCK showed significantly lower staining scores than the other five markers. There was no significant difference in staining scores among the other five markers. HMWCK showed a unique paradoxical staining pattern in clear cell lesions, with diffusely positive inner epithelial cells and completely negative outer myoepithelial cells. Although the sensitivity of HMWCK in clear cell lesions is low, with this unique paradoxical staining pattern and relatively high sensitivity in spindle cell lesions, HMWCK could be useful in diagnosing adenomyoepithelioma. In choosing immunohistochemical markers, any of the seven markers are useful, but combining HMWCK and any one of α-SMA, calponin, and p63 would be a good panel for the diagnosis of adenomyoepithelioma.
authors.affiliation: Department of Advanced Diagnosis, Division of Pathology, Nagoya Medical Center, 4-1-1, Sannomaru, Naka-ku, Nagoya, Aichi, 460-0001, Japan, MoritaniS@aol.com.
authors.forename: Suzuko
authors.initials: S
authors.lastname: Moritani
authors.forename: Shu
authors.initials: S
authors.lastname: Ichihara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
authors.forename: Masaki
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Akari
authors.initials: A
authors.lastname: Iwakoshi
authors.forename: Waki
authors.initials: W
authors.lastname: Hosoda
authors.forename: Michihiko
authors.initials: M
authors.lastname: Narita
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Nagai
authors.forename: Masami
authors.initials: M
authors.lastname: Asai
authors.forename: Nobuko
authors.initials: N
authors.lastname: Ujihira
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yuba
authors.forename: Mayumi
authors.initials: M
authors.lastname: Jijiwa
mesh_terms: D055331:Adenomyoepithelioma / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis* / Q000096:biosynthesis
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins