Abstract
The light and electron microscopic findings from a primary adenoid cystic carcinoma of the esophagus are described in a 70-year-old male patient. A large tumor from the middle to the upper intrathoracic esophagus was resected. The tumor exhibited a club shaped appearance and was histologically diagnosed as primary adenoid cystic carcinoma (ACC) of the esophagus. The patient died 5 months after surgery because of widespread distant metastasis. Histologically, the tumor showed an incomplete cribriform, duct-like or solid pattern. A small focus of squamous cell carcinoma (SCC) was found and transitional features intermediate between those of ACC and SCC were found. Under electron microscopy, the tumor cells were markedly similar to small duct cells of the normal esophageal glands. Membrane-coating granules and tonofibrils, which were found in the stratum granulosa of the esophageal squamous epithelium, were observed in the cytoplasm of the tumor cells. These results suggest that tumor cells possess the properties of both esophageal gland cells and squamous epithelial cells. It is assumed that ACC might originate from the esophageal glands, especially from small duct cells including intercalated ducts cells, and might be differentiating toward SCC.
