Comparison of the Clinicopathological Characteristics and Prognosis of Esophageal Squamous Cell Carcinoma with Intramural Metastases and Multiple Primary Carcinomas

Background It is difficult to distinguish esophageal squamous cell carcinoma with intramural metastases (IM) from multiple primary oesophageal carcinoma (MPEC). Nevertheless, there are significant differences in their prognoses and treatments. Therefore, our study aims to clarify the clinicopathological and prognostic characteristics of these two entities and to provide clues for differential diagnosis. Methods We retrospectively analyzed 6304 patients who underwent esophagectomy without neoadjuvant therapy. The clinicopathological and prognostic features of patients with IM and MPEC were evaluated. P53 and Rb1 were detected by immunohistochemical (IHC) staining using a tissue microarray. Results Among the 6304 patients, 127 (2.0%) had IM, and 138 (2.2%) had MPEC. Patients with IM were more likely to have an advanced pT (p < 0.001), pN (p < 0.001), more lymphovascular invasion (p < 0.001) and neural invasion (p < 0.001). Additionally, patients with IM had an extremely poor prognosis compared to those with MPEC, with 5-year overall survival (OS) rates of 18.9% and 56.9%, respectively. Meanwhile, IM was found to be an independent poor prognostic indicator for OS and DFS. In the IM group, all patients showed consistent p53 expression in both primary and IM foci. Of note, Rb1 loss was found in 3 pairs of primary foci and metastases, along with p53 nonsense mutation. Conclusions Patients with IM had more risk factors and extremely worse prognosis than those with MPEC. It is essential to discriminate IM from MPEC when managing multifocal carcinomas. IHC staining of p53 and Rb1 may aid in differential diagnosis.