Primary intraosseous squamous cell carcinoma arising in an odontogenic cyst - a clinicopathologic analysis of 116 reported cases

Purpose: To review the literature on primary intraosseous squamous cell carcinoma (PIOSCC) associated with odontogenic cyst. Methods: All well-documented cases of PIOSCC published between 1938 and 2010 were collected. Only cases of PIOSCC arising from the lining of an odontogenic cyst, including the keratocystic odontogenic tumor, were selected. Age, sex, signs and symptoms, affected jaw, cyst type, treatment, histopathology, and outcome were recorded. Results: The mean age was 60.2years (range 1.3-90). There were 80 (69%) men and 36 (31%) women. Mass and pain were the most common presenting symptoms. The mandible was affected in 92 (79%) patients and the maxilla in 24 (21%). It was a residual/radicular cyst in 70 (60%) patients and a dentigerous cyst or a keratocystic odontogenic tumor in the remaining 40%. The histopathology was well-differentiated SCC in 53 (46%) patients and moderately differentiated SCC in 47 (40%) patients. Fifty-three (46%) patients were treated with surgery alone and 44 (38%) with surgery and radiotherapy. Fifty-eight (62%) patients survived 2years and 36 (38%) survived 5years. Conclusion: PIOSCC has a predilection for men (M/F ratio of 2.22:1), affects mainly adults in their 6-8th decades, occurs most frequently (79%) in the mandible, and is associated mainly with a residual/radicular cyst. Histologically, the well-to-moderately differentiated SCC was the most common. Surgery alone or combined therapy of surgery and radiation was the most common approach. The prognosis is 62% surviving 2years and 38% 5years.