Impression cytology in the evaluation of ocular surface tumors: review article

Impression cytology (IC) has been widely used as a method for evaluating the ocular surface and superficial cells layers in the diagnosis and follow-up after treatment of several ocular surface tumors of both epithelial and melanocytic origin. Information regarding this can be found in the English-language literature since 1992. Using either cellulose acetate or Biopore membranes for specimen collection, a high correlation has been found between IC and tissue histology. Compared with exfoliative cytology with spatula, IC is less traumatic to the patient’s eye, provides a precise location of the area being studied, and allows accurate observation of the cells the way they exist in vivo. The additional advantage of IC is the preservation of limbal stem cells responsible for continuous corneal epithelium renewal; these can be affected after incisional or excisional biopsy at the corneoscleral limbus, which is the most frequent site of appearance of tumors in the stratified epithelium. Treatment for ocular surface squamous neoplasia has historically included surgery, but nonsurgical interventions have also been adopted. Hence, in certain cases, ophthalmologists may prefer interventions less invasive than surgical biopsy such as of impression cytology for both initial diagnosis and therapeutic monitoring of treatment for ocular surface lesions. Nevertheless, it should be considered that IC may be less helpful if the results conflict with the clinical picture or if the clinical diagnosis is uncertain and results are negative. In such cases, surgical biopsy is required for accurate diagnosis. The purpose of this review is to examine the published literature on the utilization of IC for the diagnosis and management of ocular surface tumors and to discuss the requirement for further investigation on the subject.

印迹细胞学（Impression cytology，IC）已被广泛应用于眼表及表层细胞层的评估，可用于多种上皮源性与黑素源性眼表肿瘤的诊断及治疗后随访。自1992年起，相关研究成果已见于英文学术文献。采用醋酸纤维素膜或Biopore膜采集标本时，印迹细胞学与组织病理学检查已被证实存在高度相关性。相较于使用刮铲的脱落细胞学检查，印迹细胞学对患者眼部的创伤更小，可精准定位待检测区域，还能如实观察细胞在体内的原始存在状态。印迹细胞学的另一项优势在于，可保留负责角膜上皮持续更新的角膜缘干细胞；而角膜缘作为分层上皮肿瘤最常见的发生部位，在此处进行切开或切除活检时，这类干细胞往往会受到损伤。眼表鳞状上皮肿瘤的治疗既往多采用手术方案，但目前非手术干预手段也已得到临床应用。因此在部分病例中，眼科医生更倾向于选择比手术活检创伤更小的干预方式——例如印迹细胞学——用于眼表病变的初诊及治疗过程中的疗效监测。不过需注意，若印迹细胞学结果与临床体征不符，或临床诊断存疑而细胞学结果为阴性时，该检查的辅助诊断价值可能有限。此类情况下，需通过手术活检以获取准确诊断。本综述旨在梳理已发表的关于印迹细胞学在眼表肿瘤诊断与管理中的应用的相关文献，并探讨该领域尚需开展的进一步研究方向。