Collision lesion of mandible--coexistence of keratocystic odontogenic tumor with central giant cell granuloma: a rare case report.

AIM AND BACKGROUND: An odontogenic keratocyst (OKC) or keratocystic odontogenic tumor (KCOT) and giant cell granuloma (GCG) in the jaws are common lesions which have been studied extensively in detail over the years. However, a lesion showing features of both is exceptionally rare and is reported only twice in the literature till date. CASE DESCRIPTION: A rare case of OKC in mandible showing foci of GCG like areas is reported in a 29 years old male patient. CONCLUSION: It seems to be a collision lesion, though the possibility of KCOT showing a reactive response to form giant cells or it being a rare variant cannot be totally ruled out. CLINICAL SIGNIFICANCE: This entity requires aggressive treatment since biological behavior of this unique lesion is difficult to predict unless more of such lesions are reported and followed up in future.