[Nasopharyngeal tonsillolith: a report of 31 cases]

Nasopharyngeal tonsilloliths are less well known to radiologists than palatine tonsil lithiases. The possibility of routinely available fine slices during CT scans of the head and neck prompted a retrospective study on the causes and radiological signs and patterns of nasopharyngeal tonsilloliths.

A total of 515 CT scans were retrospectively re-examined looking for calcifications of the posterior wall of the nasopharynx. One patient with this type of calcification underwent a cerebral MRI as part of the etiological workup of his faintness, which also provided a study of the nasopharyngeal wall. The size, density, and position of these calcium concretions were analyzed with CT in all cases.

In 31 patients (18 men, 13 women), we discovered one or several calcifications in the pharyngeal mucous area, between 2 and 5.5 mm in size, with a median density of 202 HU. In two cases, we observed that these calcifications adhered to an adenoid cyst, whereas in three cases, the patients had both palatine tonsil and nasopharyngeal calcifications. None of the 31 patients had previously had an adenoidectomy. Sagittal CT and MRI images clearly localized all these calcifications before the pharyngobasilar fascia.

The position of these nasopharyngeal calcifications in front of the pharyngobasilar fascia means that a calcified vestige of the notochord can be ruled out. Moreover, the simultaneous presence of nasopharyngeal tonsil and palatine tonsil calcifications in three patients is an additional argument for considering these calcifications of the posterior wall of the nasopharynx as tonsilloliths, all of which, representing 6% of the CTs in our series, were asymptomatic.

The nasopharyngeal tonsilloliths are stones less than 1 cm in size lodged in the pharyngeal tonsils that are frequently detected on CT when there are no clinical symptoms.