Benign signet ring cell change with multilayering in the gallbladder mucosa--a case report.

We describe a case of benign signet ring cell change in the gallbladder mucosa. On histopathological examination of H&E-stained sections, the gallbladder epithelium showed multilayering. The epithelial cells were large, columnar to polygonal with a small round basal or eccentric nucleus and vacuolated cytoplasm, giving them a signet ring appearance. There was no nuclear atypia, hyperchromatism or mitotic activity. The cells showed uniform positivity with mucicarmine, PAS and Alcian blue stains. The cytoplasmic vacuolations were negative for fat stains (Oil red O and Sudan IV). On immunohistochemistry, the cells showed positivity with antibodies for pancytokeratin (PCK) and epithelial membrane antigen (EMA). A diagnosis of benign signet ring cell change with multilayering in the gall bladder mucosa was made. Thoroughly reviewing the literature, we found only one case of benign signet ring cell aggregates in the gallbladder mucosa documented earlier. The lesion is hereby reported because of the unique histomorphology and the diagnostic dilemma which can occur as a malignant change in situ has to be excluded.