Esophageal adenosquamous carcinoma mimicking acantholytic squamous cell carcinoma.

Herein is described a unique case of esophageal cancer mimicking acantholytic squamous cell carcinoma (SCC). The patient succumbed to the disease within one month of diagnosis. Autopsy revealed a 10-cm esophageal tumor, characterized by prominent acantholysis-like areas composed of discohesive cancer cells, along with nested growth of SCC. These discohesive cancer cells focally exhibited pagetoid extension into adjacent esophageal epithelium, comprised ~60% of the esophageal tumor volume and had widely metastasized to the lungs, chest wall, liver, spleen, right adrenal gland, bones and lymph nodes. No metastases of SCC were observed. SCC cells were immunohistochemically positive for keratin 5/6 and E-cadherin and were negative for mucin and carcinoembryonic antigen (CEA). However, the discohesive cancer cells exhibited negativity for keratin 5/6, positivity for mucin and CEA, and diminished or no immunostaining for E-cadherin. Thus, these discohesive cells represented true adenocarcinomatous differentiation rather than acantholytic SCC cells. It was concluded that this tumor was an esophageal adenosquamous carcinoma with 'pseudo'-acantholytic adenocarcinoma components, which should be considered as a rare but distinctive type of aggressive cancer.