Peripheral type squamous cell carcinoma of the lung: clinicopathologic characteristics in comparison to the central type

• Published in: Journal of pathology and translational medicine Vol. 54; no. 4; pp. 290 - 299
• Main Authors: Sung, Yeoun Eun, Cho, Uiju, Lee, Kyo Young
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Pathologists, Korean Society for Cytopathology 01.07.2020; The Korean Society of Pathologists and the Korean Society for Cytopathology; Korean Society of Pathologists & the Korean Society for Cytopathology; 대한병리학회
• Subjects: Cloning; Cytokeratin; cytokeratin-7; Deoxyribonucleic acid; DNA; DNA methylation; Epidermal growth factor; Fatalities; lung neoplasms; Mutation; Original; Pathogenesis; peripheral; squamous cell carcinoma; Statistical analysis; Studies; Survival analysis; 병리학; United States > US
• ISSN: 2383-7837; 2383-7845
• DOI: 10.4132/jptm.2020.05.04

Background: Squamous cell carcinomas (SqCCs) of the lung are known to arise more often in a central area but reports of peripheral SqCCs have increased, with a pathogenesis that is obscured. In this study, the clinicopathologic characteristics of peripheral lung SqCCs were studied and compared with those of the central type. Methods: This study included 63 peripheral lung SqCCs and 48 randomly selected central cases; hematoxylin and eosin-stained slides of surgically resected specimens were reviewed in conjunction with radiologic images and clinical history. Cytokeratin-7 immunohistochemical staining of key slides and epidermal growth factor receptor (EGFR)IKRAS mutations tested by DNA sequencing were also included. Results: Stages of peripheral SqCCs were significantly lower than central SqCCs (p = .016). Cystic change of the mass (p = .007), presence of interstitial fibrosis (p=0.007), and anthracosis (p=.049) in the background lung were significantly associated with the peripheral type. Cytokeratin-7 positivity was also higher in peripheral SqCCs with cutoffs of both 10% and 50% (p = .011). Pathogenic mutations in EGFR and KRAS were observed in only one case out of the 72 evaluated. The Cox proportional hazard model indicated a significantly better disease-free survival (p=.009) and the tendency of better overall survival (p=.106) in the peripheral type. Conclusions: In peripheral type, lower stage is a favorable factor for survival but more frequent interstitial fibrosis and older age are unfavorable factors. Multivariate Cox analysis revealed that peripheral type is associated with better disease-free survival. The pathogenesis of peripheral lung SqCCs needs further investigation, together with consideration of the background lung conditions.