Comparison of calretinin expression in dentigerous cysts and ameloblastoma: An immunohistochemical study

BACKGROUND: Calretinin is a calcium-binding protein of 29-kilodalton (kDa), which is widely expressed in normal human tissues and tumorigenic tissues. Its expression in the odontogenic epithelium during odontogenesis and in neoplastic odontogenic tissues has been demonstrated. Unicystic ameloblastoma poses a diagnostic challenge, as its histologic presentation can be sometimes mistaken for cystic odontogenic lesions. In the present study, an attempt is made to overcome the confusion encountered in the diagnosis of dentigerous cyst and unicystic ameloblastoma, using the expression of calretinin in both lesions and to compare this expression with conventional ameloblastoma to accurately diagnose and differentiate these lesions. MATERIALS AND METHODS: A total of eighty cases, in which twenty cases each of ameloblastoma, unicystic ameloblastoma, dentigerous cyst, and odontogenic keratocyst (OKC) were included in the study. Slides were made from the archival blocks of each case and were stained immunohistochemically with calretinin. RESULTS: Correlation between calretinin staining and histopathological diagnosis was done, and it was found that all twenty cases of ameloblastoma showed positivity for calretinin, whereas 17 of twenty cases of unicystic ameloblastoma showed positivity for calretinin staining. All the cases of OKC and dentigerous cyst were negative for calretinin. CONCLUSION: Calretinin may serve as an important diagnostic adjunct in the differential diagnosis of ameloblastoma and cystic odontogenic lesions.