A single ThinPrep® slide may not be representative in all head and neck fine needle aspirate specimens

Objectives:  Ideally, head and neck aspiration should be performed by trained aspirators within the setting of a one-stop clinic, where smeared material is available for immediate assessment. However, this may not always be possible for practical reasons and the use of liquid-based techniques in head and neck cytology is increasing. Although liquid-based cytology has been extensively validated for use in gynaecological cytology, no studies have investigated whether or not a single ThinPrep ^® slide is representative for head and neck aspirate specimens. We performed a prospective audit of head and neck fine needle aspiration specimens processed by the ThinPrep ^® method to investigate whether a single ThinPrep ^® slide was representative.
Methods:  A prospective audit of 115 consecutive head and neck aspirates was carried out. A single ThinPrep ^® slide was prepared and a diagnosis recorded. The remainder of the specimen was then spun down and prepared as a cell block. The ThinPrep ^® and cell block diagnoses were compared.
Results:  In 36 cases (31%), the cell block provided additional information that contributed to the diagnosis. In 14 (12%), the cell block was regarded as essential to the diagnosis.
Conclusions:  A single ThinPrep^® slide may not provide representative diagnostic material in all head and neck aspirates. This should be taken into consideration when contemplating the use of liquid-based methods for non-gynaecological cytology.