Parathyroid identification by ultrasonically guided aspiration cytology

Reliable parathyroid identification is necessary before percutaneous inactivation of parathyroid tumours is carried out. Aspiration cytology is one of the methods used for this purpose. Some, but not all, investigators have found it difficult or impossible to make a cytological distinction between thyroid and parathyroid cells. In a blind morphological study of 16 parathyroid and 16 thyroid aspirations the specificity of a cytological diagnosis of parathyroid cells was 100%. The sensitivity of the same diagnosis was 9/16 = 56% if only certain diagnosis of parathyroid cells was considered, but 14/16 = 88% if also diagnoses of “probably parathyroid cells” were considered.