A Case of Coexistence of Esophageal Squamous Cell Carcinoma and Adenocarcinoma.

Esophageal malignancy is a prevalent cancer both in the United States and globally. In the United States, adenocarcinoma is a particularly common esophageal malignancy, likely secondary to gastroesophageal reflux disease (GERD) and Barrett's esophagus. Conversely, squamous cell carcinoma (SCC) is the most common histology globally, especially prevalent in Asian countries, in what is known as the esophageal cancer belt. SCC and adenocarcinoma of the esophagus have clinical, oncologic, and histologic differences suggesting the need for tailored therapeutic approaches. In some cases, patients with concurrent risk factors for both malignancies can present with a collision tumor or adjacent tumors with two histologic subtypes within a single mass, and this warrants a unique treatment strategy. A case such as this one, involving a patient presenting with simultaneous poorly differentiated SCC as well as high-grade adenocarcinoma in the background of tubulovillous adenoma-like change, presents a unique clinical course and a possible example of a collision tumor. Furthermore, the differing prognostic indicators for both squamous and adenocarcinoma of the esophagus can highlight the importance of individualized treatment plans to improve both patient satisfaction and quality of life.