Submucosal layer invasion of squamous cell carcinoma in situ and its differentiation to endocrine cell carcinoma in a case of superficial carcinoma at the esophagogastric junction

Endocrine cell carcinoma (ECC) of the esophagogastric region is a rare malignancy with varied etiologies. In this report, we describe a 64-year-old patient in whom a superficial carcinoma at the esophagogastric junction was detected via endoscopy. No metastasis was noted, and the patient underwent total gastrectomy. During a 1-year follow-up, there was no evidence of recurrence or metastasis. Upon histological analysis, the lesion was found to comprise squamous cell carcinoma (SCC) with an in situ component and a component that had invaded the submucosal layer, in addition to an ECC component. There was no indication of a collision carcinoma, and Nanog negativity excluded the possibility that a cancer stem cell etiology could explain the different cell types. The evidence suggested differentiation from SCC to ECC during the progression to invasive SCC. We describe the possibility of SCC differentiation into ECC and discuss the associated controversial issues.