title: Primary epithelial-myoepithelial carcinoma of the lung: A case report demonstrating high-grade transformation-like changes.
abstract: Primary salivary gland-type tumors of the lung are rare; among them, epithelial-myoepithelial carcinomas (EMC) represent a minor histological subtype. The present case documents an EMC that occluded the B8 segment of the left lung in a 72-year-old woman. Macroscopically, the tumor was well-demarcated; however, microscopic examination demonstrated that it had infiltrated the lung parenchyma. The majority of the tumor mass was composed of a myoepithelial overgrowth in conjunction with conventional bilayered ductal structures comprising epithelial and myoepithelial cells. At the advancing edge of the tumor, the myoepithelial overgrowth was observed to be gradually transitioning to a higher-grade component, which demonstrated venous invasion. The Ki-67 labeling index was reduced compared with high-grade transformation (HGT) of salivary gland EMC; p53 was sparsely observed on immunostaining. However, cyclin D1, which is reported to be overexpressed in certain subtypes of salivary gland carcinomas with HGT, was overexpressed in the higher-grade component of the tumor, indicating a potential HGT initiation. The surgical margin was tumor free, and no recurrence has been observed for 4 months. A thorough follow-up is required considering the HGT-like changes and venous invasion of the tumor. Additional studies are required to elucidate the characteristics of pulmonary EMC, with an emphasis on detecting HGT or HGT-like changes.
authors.affiliation: Department of Pathology, Shizuoka Saiseikai General Hospital, Shizuoka, Shizuoka 422-8021, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Tajima
authors.affiliation: Department of Cell Biology and Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan.
authors.forename: Michihiko
authors.initials: M
authors.lastname: Aki
authors.affiliation: Department of Chest Surgery, Fujieda Municipal General Hospital, Fujieda, Shizuoka 426-0077, Japan.
authors.forename: Kiyoshige
authors.initials: K
authors.lastname: Yajima
authors.affiliation: Department of Chest Surgery, Fujieda Municipal General Hospital, Fujieda, Shizuoka 426-0077, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Chest Surgery, Fujieda Municipal General Hospital, Fujieda, Shizuoka 426-0077, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Neyatani
authors.affiliation: Department of Pathology, Fujieda Municipal General Hospital, Fujieda, Shizuoka 426-0077, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Koda
keywords: cyclin D1; epithelial-myoepithelial carcinoma; high-grade transformation; lung