Abstract
Purpose: :
To describe and illustrate a hierarchy of steps that can lead to correct cytodiagnosis of solid intraocular tumors evaluated by fine–needle aspiration biopsy (FNAB).
Methods: :
Retrospective descriptive report based on an extensive experience with more than 400 fine–needle aspiration biopsies over the past 25 years.
Results: :
The first step in pathologic diagnosis of fine–needle aspiration biopsy specimens of solid intraocular tumors is cytomorphological analysis of slides stained with conventional chemical stains (e.g., hematoxylin & eosin, periodic acid Schiff, Papanicolaou). During this part of the analysis, the pathologist evaluates features such as quantity of cells, cohesiveness of the cells, size and shape of the cells, their nuclei and their nucleoli, the nuclear to cytoplasmic ratio of the cells, the presence or absence of cytoplasmic inclusions, the uniformity versus pleomorphism of the cells, and the mitotic activity of the tumor cells. The second step is cytochemical analysis of the tumor cells with special chemical stains designed to identify specific intracellular chemical components (e.g., Fontana stain for melanin, Alcian blue stain for mucin) that help establish the nature of those cells. The third step is immunocytochemical analysis of the tumor cells for various tumor markers (e.g., uveal melanoma markers such as HMB–45 and Melan–A, carcinoma markers such as AE1/AE3 and cytokeratin, lymphoid markers such as leukocyte common antigen and the various CD antigens, neural ectodermal markers such as S–100 protein and neuron specific enolase, neuroendocrine markers such as synaptophysin and chromogranin) the pathologist suspects may be present on the basis of the cytomorphological and cytochemical features.
Conclusions: :
Pathologic analysis of FNAB aspirates routinely involves cytomorphological analysis of slides stained by conventional chemical stains. If the specimen is sufficient, additional special chemical stains and/or immunocytochemical stains can be performed to further refine the diagnosis. The amount of cells in the aspirates and the availability of the various special stains and immunostains in the laboratory evaluating the aspirates appear to be the major determinants of how many of these steps are taken in any given case.
Keywords: oncology • cytology • pathology techniques