Objective: To analyze ThinPrep (TP) application by comparing TP slides with conventional smear (CS) slides in fine needle aspiration cytology.
Methods: A total of 522 samples from the breast, metastatic cancer, lymph node, thyroid and salivary gland were used in parallel preparations of one TP slide and one CS slide. The paired slides were compared according to cell quality, overall cellularity, cell preservation, nuclear architecture and background.
Results: Cell quality of TP was superior to CS in the breast group (36.2%, 28.0%, P > 0.05) and metastatic cancer group (51.0%, 14.9%, P < 0.05), but inferior to CS in lymph node group (16.5%, 58.2%, P > 0.05). Cellularities of TP and CS were similar in breast groups (25.1%), while TP had greater cellularity than CS in metastatic cancer group (32.2%, 21.8%, P > 0.05). Cell preservation and abnormal architecture of TP were superior to CS in breast group (36.7%, 12.1%, P < 0.05) and metastasis cancer group (60.9%, 9.4%, P < 0.05). Cell quality of TP slide was inferior to CS in lymph node group (16.5%, 58.2%, P < 0.05) with 27 of the 46 cases showing tuberculosis. Cell quality of TP and CS slide was similar in the thyroid and salivary gland group (35.3%). Myoepithelial cells of fibroadenoma on the TP slide were decreased in number and, due to the increased papillary and flattened cells, it was easy to diagnose benign lesion.
Conclusion: In the breast group and metastatic cancer group, cell quality of the TP slides is superior to CS, but they are similar in thyroid and salivary gland group. The difference of diagnosis criteria between TP and CS slides exists only in tuberculosis, partly the reactive hyperplasia cases.