title: Pyloric gland type adenoma of the gallbladder with squamoid spindle cell metaplasia.
abstract: This study documents a pyloric gland type adenoma of the gallbladder with prominent spindle cell metaplasia arising in a 61 year-old woman. A pedunculated polyp, 1.5 x 1.0 x 1.0 cm, was histologically diagnosed as a tubular adenoma. Most glandular structures showed positivity for a monoclonal antibody M2 (2B5) which indicates a differentiation to pylotic gland type. The spindle cell component displayed no apparent epithelial structures but stained mostly positive for pancytokeratin and cytokeratin (CK) 18, and focally for CK 5 + 6, CKs 7 and 19, whereas CKs 8, 13, 20, and non-epithelial markers could not be demonstrated. This suggests that the spindle cells were immature epithelial cells differentiating towards squamous and/or glandular cells. Even in spindle cell areas, the nuclear atypia was mild, and proliferating cells positive for MIB-1 (Ki-67) antigen were infrequently seen. This unique phenomenon, of which only three cases have been previously reported, is considered to represent benign squamoid spindle cell metaplasia.
authors.affiliation: Department of Pathology, Shiga University of Medical Science, Otsu, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kushima
authors.forename: W
authors.initials: W
authors.lastname: Remmele
authors.forename: M
authors.initials: M
authors.lastname: Stolte
authors.forename: F
authors.initials: F
authors.lastname: Borchard
mesh_terms: D000236:Adenoma / Q000473:pathology*; D004817:Epidermis / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D005260:Female; D005706:Gallbladder Neoplasms / Q000473:pathology*; D006801:Humans; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D018307:Neoplasms, Squamous Cell / Q000473:pathology; D011708:Pylorus / Q000473:pathology*