Entirely Intramural Growth Pattern: A Rare Presentation of Esophageal Squamous Cell Carcinoma and Review of the Literature

Background Esophageal squamous cell carcinoma (ESCC) is a malignant tumor originating from the squamous epithelium. In contrast, esophageal submucosal tumors are common benign lesions arising from mesenchymal tissues. To date, an entirely intramural growth of ESCC is very rare. This study described a case of an esophageal submucosal tumor resected by endoscopic submucosal dissection (ESD) that was finally diagnosed as ESCC. Case report A 51-year-old woman presented with progressive dysphagia and was provisionally diagnosed with esophageal leiomyoma by further diagnostic modalities. The patient did not have any obvious suspicious malignant features and underwent ESD. However, the histopathology of the resected specimen was reported as poorly differentiated infiltrating squamous cell carcinoma with normal overlying squamous epithelium. Consequently, the patient received additional chemoradiotherapy, and no recurrence was observed during the 2-year follow-up. Literature review A comprehensive literature search related to ESCC with entirely intramural growth was performed in PubMed and Embase from their inception up to November 2023, and 12 articles including 13 cases were finally included in the literature review. Subsequently, we extracted information about these cases. Conclusion It is concluded that ESCC may masquerade as a submucosal tumor with a complete submucosal growth pattern and is easily misdiagnosed because endoscopic biopsy and iodine staining are always negative. Therefore, if a patient with a submucosal tumor has dysphagia or weight loss in the short term, clinicians should be alert to the possibility of ESCC with a complete submucosal growth pattern. Endoscopic ultrasonography (EUS), chest computed tomography (CT), or positron emission tomography-computed tomography (PET-CT) may help assist in the diagnosis, and EUS-guided fine-needle aspiration (EUS-FNA) could be used to confirm the diagnosis.