TY - JOUR
T1 - Salivary mucoepidermoid carcinoma
T2 - histological variants, grading systems, CRTC1/3-MAML2 fusions, and clinicopathological features
AU - Nakano, Satsuki
AU - Okumura, Yoshihide
AU - Murase, Takayuki
AU - Nagao, Toshitaka
AU - Kusafuka, Kimihide
AU - Urano, Makoto
AU - Yamamoto, Hidetaka
AU - Kano, Satoshi
AU - Tsukahara, Kiyoaki
AU - Okami, Kenji
AU - Kawakita, Daisuke
AU - Nagao, Toru
AU - Hanai, Nobuhiro
AU - Iwai, Hiroshi
AU - Kawata, Ryo
AU - Tada, Yuichiro
AU - Nibu, Ken Ichi
AU - Inagaki, Hiroshi
N1 - Publisher Copyright:
© 2021 John Wiley & Sons Ltd
PY - 2022/3
Y1 - 2022/3
N2 - Aims: To investigate the histological diversity of salivary mucoepidermoid carcinoma (MEC), its clinicopathological features, and its associations with CRTC1/3-MAML2 fusions. Methods and results: Salivary MEC cases (n = 177) were examined for CRTC1/3-MAML2 fusions, histological variants were classified, and tumours were graded according to four different grading systems. Adverse histological features considered to be unusual in MEC were also investigated. Of the 177 MEC cases, 110 were positive for CRTC1/3-MAML2 fusions. The classical variant was the most frequent in the fusion-positive case group, the fusion-negative case group, and the total case group. The clear/oncocytic variant was the second most frequent in the fusion-positive and total case groups. Oncocytic, Warthin-like and spindle variants were seen in the fusion-positive case group only. Clear cell, sclerosing, mucinous and central variants were seen in both the fusion-positive case group and the fusion-negative case group. No case was classified as a ciliated variant, as a mucoacinar variant, or as a high-grade transformation. As compared with the classical variant, non-classical variants were characterised by frequent CRTC1/3-MAML2 fusions and a low clinical stage in all cases. Of the four histological features considered to be unusual in MEC, marked nuclear atypia, frequent mitoses (>10/10 high-power fields) and extensive necrosis were found independently of the fusion status, and were present in 3–5% of all cases. However, none of the cases showed overt keratinisation. On comparison, the Armed Forces Institute of Pathology and modified Healey grading systems downgraded tumours, the Brandwein system upgraded tumours, and the Memorial Sloan Kettering system provided a moderate means of assessment. Conclusion: Recognition of the histological diversity of MEC, its clinicopathological features and its associations with CRTC1/3-MAML2 fusions is helpful for an accurate diagnosis of this carcinoma.
AB - Aims: To investigate the histological diversity of salivary mucoepidermoid carcinoma (MEC), its clinicopathological features, and its associations with CRTC1/3-MAML2 fusions. Methods and results: Salivary MEC cases (n = 177) were examined for CRTC1/3-MAML2 fusions, histological variants were classified, and tumours were graded according to four different grading systems. Adverse histological features considered to be unusual in MEC were also investigated. Of the 177 MEC cases, 110 were positive for CRTC1/3-MAML2 fusions. The classical variant was the most frequent in the fusion-positive case group, the fusion-negative case group, and the total case group. The clear/oncocytic variant was the second most frequent in the fusion-positive and total case groups. Oncocytic, Warthin-like and spindle variants were seen in the fusion-positive case group only. Clear cell, sclerosing, mucinous and central variants were seen in both the fusion-positive case group and the fusion-negative case group. No case was classified as a ciliated variant, as a mucoacinar variant, or as a high-grade transformation. As compared with the classical variant, non-classical variants were characterised by frequent CRTC1/3-MAML2 fusions and a low clinical stage in all cases. Of the four histological features considered to be unusual in MEC, marked nuclear atypia, frequent mitoses (>10/10 high-power fields) and extensive necrosis were found independently of the fusion status, and were present in 3–5% of all cases. However, none of the cases showed overt keratinisation. On comparison, the Armed Forces Institute of Pathology and modified Healey grading systems downgraded tumours, the Brandwein system upgraded tumours, and the Memorial Sloan Kettering system provided a moderate means of assessment. Conclusion: Recognition of the histological diversity of MEC, its clinicopathological features and its associations with CRTC1/3-MAML2 fusions is helpful for an accurate diagnosis of this carcinoma.
KW - CRTC1/3-MAML2 fusions
KW - clinicopathological correlations
KW - histological variants
KW - mucoepidermoid carcinoma
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U2 - 10.1111/his.14586
DO - 10.1111/his.14586
M3 - Article
C2 - 34657306
AN - SCOPUS:85121321428
SN - 0309-0167
VL - 80
SP - 729
EP - 735
JO - Histopathology
JF - Histopathology
IS - 4
ER -