[Thornwaldt's cyst. The experience of a decade].

The cyst of the Thornwaldt's bursa is a bulge on the postero-superior wall of the rhinopharynx, due to the closure of the sac's drainage duct. The bursa pharyngea being an embryologic remnant occurring in 3 percent of healthy adults. It is a process well known since a century, but only 11 cases (in 9 several publications) have been quoted in the last 20 years.