OBJECTIVETo study the clinicopathologic features and differential diagnosis of adenoid cystic carcinoma in the esophagus.

METHODSTen cases of primary adenoid cystic carcinoma of the esophagus were retrieved from the archival file. The clinicopathologic and immunohistochemical features were studied. The differential diagnosis was analyzed.

RESULTSThe male-to-female ratio was 9: 1. The age of patients ranged from 59 to 76 years. There were 4 cases with tumor located in mid esophagus, 4 cases with tumor located in mid to lower esophagus and the remaining 2 cases in lower esophagus. Low-power histologic examination showed mainly expansive growth pattern, with cribriform, solid and focal tubular architectures identified. The tumor cells showed nuclear hyperchromasia. Both ductal and myoepithelial differentiation was demonstrated. The stroma showed myxoid degeneration in areas. Comedo-type necrosis was observed in 8 cases and moderate to severe squamous dysplasia was present in one case. Three cases showed focal areas of squamous cell carcinoma. Immunohistochemical study showed that the tumor cells were positive for p63 (10/10), CD117 (10/10) and S-100 protein (9/10). There was focal staining for calponin (2/10) and smooth muscle actin (2/10). The ductal structures expressed CK7 (10/10).

CONCLUSIONSAdenoid cystic carcinoma of the esophagus demonstrates unique morphologic features with expression of S-100 protein and consistent expression of CD117. The above characteristics help to distinguish this entity from basaloid squamous cell carcinoma, mucoepidermoid carcinoma and small cell carcinoma of the esophagus.