Eyelids cytology: general aspects

Skin lines the eyelids externally and the conjunctiva lines the inner surface; cytological sampling and microscopic examination of these areas are similar to those of other sites. Scraping is the most commonly used technique for cytological diagnosis of skin and mucosa and may be performed by skillful cytopathologists, whereas sampling of lesions of the cantus or the rim should be performed by ophthalmologists. Scrapings may be performed without anaesthesia using a specific spatula or the blunt side of a scalpel blade. When suspected lesions are not ulcerated it may be necessary to lift or remove the external epidermal layer covering the lesion. This can be achieved by using the sharpened edge of a scalpel blade to gently cut through the superficial layer of the epidermis and thus allow the scraping of the deeper one. Smears are prepared as previously described and may be fixed in alcohol and stained by the Papanicolaou method or air-dried and stained with May-Grümwald-Giemsa (MGG) or Diff-Quik. As in other regions, MGG or Diff-Quik stainings are generally suitable for the demonstration of bacteria and to diagnose lymphoid and mesenchymal tumours, while the Papanicolaou method is preferable for epithelial or melanocytic tumours