Objective: To describe the cotton block method, an easy, inexpensive, 1-step method of obtaining a cell block after fine needle aspiration biopsy.
Study design: Before connection to a 10-mL syringe, the plastic hub of a 22-23-gauge needle is filled with the 3-4-mm, woolly tip of a cotton bud. Aspiration is performed as described elsewhere. After smear preparation, the material remaining in the needle and the material retained in the cotton wool mesh are immediately fixed by aspiration ofa fixative fluid (70% alcoholic formaldehyde-acetic acid). After fixation, the cotton tip is removed and routinely processed for paraffin embedding, and the sections are stained by routine methods used in cytopathology.
Results: The results demonstrate that the amount and quality of material obtained in the cotton wool tip is similar to that in the traditional cell block obtained from the pellet after centrifugation of aspirated fluid.
Conclusion: The method is easy to perform and cost effective and is a rapid way to prepare cell blocks of high quality, allowing special staining techniques and improving cytohistologic correlation.