Eyelids, orbit and eye

The eyelids, orbit and eye represent probably one of the most complex and difficult anatomical regions to investigate cytologically, and one which cytopathologists are rarely requested to investigate. In fact, non-invasive diagnostic procedures such as optical coherence tomography (OCT) or A/B scan ultrasonography have significantly reduced the need for examination of tissues or cells (1). This is mainly the case for the ocular globe and some of the orbital masses. The reduction or absence of routine cytology increases the difficulties of the cytopathologist. In fact, with the exception of some highly specialized centres, in most cases cytopathologists are involved only in the diagnosis of rare pathologies, complex clinical settings or unusual presentations. Complexity and difficulties arise also from other factors: indeed, despite the anatomical unity (Fig. 34.1), every component of this region presents its own peculiarities in terms of anatomy, variety of pathologies, diagnostic requests and technical approaches for obtaining cytological samples. Moreover, anatomical and clinical peculiarities require close cooperation between ophthalmologists and cytopathologists. The latter must be aware that clinical strategies and sampling are almost exclusively the task of ophthalmologists whereas their role should be, apart from diagnosis, the management of diagnostic material and the evaluation of adequacy, including the choice of ancillary techniques. Even when these difficulties are overcome and cytopathologists may deal with their more familiar smears, they have to face other difficulties such as scanty cellular samples from different and sometimes complex or rare pathologies. Cytopathologists have also to adapt their mindset to the different kinds of cytological samples used to diagnose a wide spectrum of pathologies. These range from exfoliative cytology for conjunctival smears, to cytology of fluids for aqueous paracentesis and fine needle aspiration (FNA) for choroid or orbital masses. Finally, ophthalmic cytology, as in other regions, has been improved by immunocytochemistry (ICC) (2), flow cytometry (FC) (3) fluorescence in-situ hybridization (FISH) (4) and molecular techniques (5-6) which further increase the complexity of or even replace cytological diagnoses. The only advantage for ophthalmic-cytopathologists, the existence of excellent books in this field (7,8,9) including the previous edition of this book, represents an additional difficulty for the authors, who are supposed to produce something better! This chapter will summarize the anatomy of the eye, eyelid and orbit and try to focus on its relationship with sampling methods. The cytopathological features of the different pathological entities in each anatomical region will then be described.