[Primary or secondary malignant tumors of tonsillar cysts. Apropos of a case of occult papillary cancer of the thyroid disclosed by intracystic metastasis].

The development of a malignant process within a tonsillar cyst is controversial. This phenomenon is exceptionally rare, at present only three cases which have been compatible with anatomo-clinical diagnostic criteria have been clearly established. Based on an original case showing a secondary papillary thyroid cancer in a tonsillar cyst, the authors analyse, in the light of recent data from worldwide literature, the various stages in the diagnostic process in both primary and secondary malignant tumours. The therapeutic and prognostic aspects of the two tumour varieties are also discussed.