Type B2 vessels and infiltrative growth patterns b and c are associated with lymphatic invasion in pT1a-lamina propria mucosa esophageal squamous cell carcinoma.

Abstract

Background: Tumor growth pattern correlates with outcomes in patients with esophageal squamous cell carcinoma (ESCC), however, the clinical significance of the tumor growth pattern in pT1a-lamina propria mucosa (LPM) type of ESCC was unclear. This study was conducted to clarify clinicopathological features of tumor growth patterns in pT1a-LPM type ESCC and the relationship between tumor growth patterns and magnifying endoscopic findings.

Methods: Eighty-seven lesions diagnosed as pT1a-LPM ESCC were included. Clinicopathological findings including tumor growth pattern and narrow band imaging with magnifying endoscopy (NBI-ME) in the LPM area were investigated.

Results: Eighty-seven lesions were classified as infiltrative growth pattern-a (INF-a): expansive growth (n = 81), INF-b: intermediate growth (n = 4) and INF-c: infiltrative growth pattern (n = 2). Lymphatic invasion was shown in one INF-b and one INF-c lesion. NBI-ME and histopathological images were matched for 30 lesions. The microvascular pattern was classified into types B1 (n = 23) and B2 (n = 7) using the JES classification. All 23 type B1 lesions were classified as INF-a without lymphatic invasion. Type B2 lesions were classified as INF-a (n = 2), INF-b (n = 4) and INF-c (n = 1), and lymphatic invasion was present in two lesions (INF-b and INF-c). The rate of lymphatic invasion was significantly higher in type B2 than type B1 (p = 0.048).

Conclusions: The tumor growth pattern of pT1a-LPM ESCC was mostly INF-a in type B1 patterns. Type B2 patterns are rarely present in pT1a-LPM ESCC, however lymphatic invasion with INF-b or INF-c was frequently observed. Careful observation before endoscopic resection with NBI-ME is important to identify B2 patterns to predict histopathology.