OBJECTIVETo investigate clinicopathological and immunohistochemical features of 31 cases of oral teratoid cyst.

METHODSThirty-one cases of oral teratoid cyst according with Meyer's diagnosis criteria were retrospectively studied and their histochemistry and immunohistochemistry were performed from the files of Department of Pathology, School of Stomatology, Wuhan University between 1963 and 2003.

RESULTSTwenty-seven cases (87.10%) were children, and twenty-four cases were congenital. The ratio of male-to-female was 1:0.55, and the affected sites were floor of mouth (22 cases) and tongue (8 cases). Clinical findings were nonspecific, and prognosis was good following complete excision. Histology indicated that squamous, respiratory and/or gastrointestinal epithelium consistiuted basic structure of teratoid cyst in addition to simple cuboidal epithelium in 8 cases. Antibody against AE1/AE3 was strongly expressed and CK16 was weak in four types of epithelial lining of oral teratoid cyst. Expression of AE1, CK7, 8/18, 19 varied in superficial, suprabasal and basal cells of squamous epithelium but were strong in respiratory, gastrointestinal and simple columnar epithelium; only gastrointestinal epithelium expressed CK20 heterogeneously.

CONCLUSIONSOral teratoid cyst showed the highest incidence in children, and floor of mouth and tongue were mostly affected sites. Features of histology were complex, and immunohistochemistry indicated that epithelium of oral teratoid cyst shared similar patterns of cytokeratin with counterpart of normal tissues, showing different origin and differentiation of epithelial lining of the present cyst.