Fine needle aspiration (FNA) biopsy of orbital masses: a critical review of 51 cases.

FNA biopsy of 51 orbital masses is critically reviewed. Aspiration was performed with a 23 G needle inserted by an ophthalmologist; the smears were prepared by a cytologist. Forty-two cases (83%) were correctly diagnosed as benign or malignant either with (68%) or without (15%) correct specification of the histology. There were two false-negative and seven inadequate cases. Immunocytochemical stains were performed in five cases using the following antibodies: L26 (Pan B), UCHL1 (Pan T), kappa and lambda immunoglobulin light chains (three cases) in order to distinguish inflammatory pseudotumours from low-grade non-Hodgkin's lymphomas. In two cases we used CAM 5.2 (a monoclonal cytokeratin cocktail) and vimentin to ascertain the epithelial origin of two metastatic tumours. In five other cases cytospins were not adequately cellular for immunocytochemistry. Insufficient material and one false-negative sample were obtained from very fibrotic lesions or from posteriorly located lesions. The results are discussed and compared with other series reported in the literature. Orbital FNA biopsy may be considered a useful tool in the diagnostic approach to orbital masses in which the relatively high number of inadequate aspirations is offset by a low cost-benefit ratio.