Esophageal Intramural Pseudodiverticulosis: A Histopathological and Immunohistochemical Study of 2 Cases.

Esophageal intramural pseudodiverticulosis (EIPD) is a rare disorder characterized by an abnormal, cyst-like dilatation of the excretory ducts of esophageal submucosal glands. We aimed to elucidate the histopathological features and immunohistochemical properties of the epithelial lining of the cyst-like lesions in EIPD. We performed a histopathological and immunohistochemical study of 2 cases (one autopsy and one surgical) of EIPD. The ductal walls consisted of inner ductal cells, which were cytokeratin (CK) 7-positive and CK5/6-negative, and outer basal cells, which were CK7-negative and CK5/6-positive. The ductal epithelium frequently showed squamous metaplasia and rarely simulated a false diverticulum. Immunohistochemistry for CK7 was useful for distinction between the conditions because the surface epithelium was negative for CK7. We also confirmed that myoepithelial cells in the acinar portion of submucosal glands were well-preserved in EIPD, the finding that explained the periodic opening and closing movements of orifices of cyst-like lesions in this disorder. The immunohistochemical properties of the epithelial lining of cyst-like lesions in EIPD were essentially similar to those of the normal ducts of submucosal glands.