The utility of vapor fixation for cell block preparation in fine needle aspiration of malignant lesions of lymph nodes

Cell blocks overcome certain limitations of fine needle aspiration cytology (FNAC), such as study of tissue architecture and application of immunohistochemistry (IHC). The main disadvantage of cell block by conventional method is cell loss. This study compares formaldehyde vapor-fixed cell blocks with conventional formalin-fixed blocks obtained from aspirates of malignant lesions of lymph nodes. Seventy-nine patients with suspected primary or metastatic malignancy in lymph nodes were studied. Cytologic smears were prepared in all the cases. Conventional formalin-fixed cell blocks were made in 34 cases, vapor-fixed cell blocks in 34 cases, and in the remaining 11 cases, both methods were employed. Cell block sections were compared for cellularity, fixation artifacts, morphologic details, and crispness of immunohistochemical staining using defined subjective criteria. Cellular yield was slightly less with vapor-fixed cell blocks in comparison with conventional formalin-fixed cell blocks. Staining artifacts ...