The clinical value of in vivo confocal microscopy for diagnosis of ocular surface squamous neoplasia

Abstract

Purpose: To determine the reliability and efficiency of in vivo confocal microscopy for the diagnosis of ocular surface squamous neoplasia (OSSN).

Methods: A case series with five consecutive cases of OSSN were investigated retrospectively, of which the characteristics and subspecial types had been estimated by in vivo confocal microscopy before surgery. The structure and cellular features of OSSN were analyzed with other examinations, such as anterior-segment optical coherence tomography (AS-OCT), and confirmed by histopathological biopsy.

Results: The tumors revealed red gelatinous surfaces with vascular dilatation on the ocular surface of the conjunctival and corneal epithelium in anterior segment photography. Involvement of only corneal epithelium was observed by AS-OCT in three cases, whereas the Bowman's layer and anterior stroma were also invaded in the other two cases. In vivo confocal microscopy showed cellular anisocytosis and enlarged nuclei with high nuclear to cytoplasmic ratio in three cases diagnosed as conjunctival intraepithelial neoplasia; moreover, nests were partially formed by isolated keratinized, binucleated, and actively mitotic dysmorphic epithelial cells in the other two cases diagnosed as carcinoma in situ and ocular surface squamous carcinoma (OSSC). The characteristics assessed from histopathological biopsy were similar to that revealed by in vivo confocal microscopy in all five cases.

Conclusion: In vivo confocal microscopy analysis of cytological characteristics of OSSN is a safe, relatively noninvasive, and effective diagnostic tool in detecting characteristics of OSSN before surgical resection. Although in vivo confocal microscopy cannot replace excisional biopsy for definitive diagnosis, it can be valuable for initial diagnosis and management of patients with OSSN.

Figure 1

Anterior-segment photography of the tumors. The tumors revealed red gelatinous appearance with vascular dilatations invading the temporal, superior, or inferior bulbar conjunctiva in all the patients. The tumors invaded peripheral corneal limbal circumference for 90–180° (CIN) (a–c), 240° (carcinoma in situ) (d), and 270° (OSSC) (e). (f) OSSN was excised and partial lameral keratoplasty was performed.

Figure 2

AS-OCT findings of the tumors. AS-OCT revealed that the extensive abnormal ocular surface tumors arose from limbal and invaded into conjunctival and corneal surface, where normal structures of conjunctival and corneal epithelium layer were destroyed and the density of large fibrovascular structures became irregular. (a, b) The tumor did not invade the Bowman's layer in three patients diagnosed as CIN (white arrows). (c) The tumor invaded the Bowman's layer in one patient diagnosed as carcinoma in situ (white arrow with big head). (d) The tumor invaded beneath the Bowman's layer and into anterior stroma in another patient diagnosed as OSSC (white dashed arrows).

Figure 3

Representative pictures from in vivo confocal microscopy. In vivo confocal microscopy on the OSSN revealed different types of abnormal squamous epithelial cells. In three cases diagnosed as CIN, (a) abnormal squamous epithelial cells were enlarged, irregular, and pleomorphic in shape (blue arrows), (b) cellular anisocytosis and anisonucleosis (blue arrows), (c) enlarged nuclei with high nuclear to cytoplasmic ratio, highly reflective cytoplasm, and indistinct cytoplasmic borders (blue arrows) were observed. (d, e) Isolated, keratinized, binucleated, and actively mitotic dysmorphic epithelial cells were observed in one case diagnosed as carcinoma in situ (red arrows. (f) No invasive cells were observed in the stroma layer in patients with carcinoma in situ. (g, h) Nests were partially formed in one case diagnosed as OSSC (yellow arrows). (i) Squamous neoplastic cells invaded into basement membrane, the Bowman's layer, and anterior stroma layer in the same case to form nests (yellow arrows).

Figure 4

Histopathological analysis of OSSN by H&E staining. (a) Enlarged and irregular squamous epithelial cells with abnormal density of cells (CIN). (b) Binucleated, actively mitotic dysmorphic cells (black arrows) and cells with increased nuclear/cytoplasm ratio were observed in patients diagnosed as carcinoma in situ. (c) Heteromorphic abnormal epithelial cells with partially formed carcinoma cell nests in OSSC were revealed (thick white arrows). The abnormal squamous epithelial cells (d) did not invade the Bowman's layer (black stars) in three cases diagnosed as CIN; (e) invaded but did not penetrate the Bowman's layer (black stars) in one case diagnosed as carcinoma in situ (black arrow); and (f) invaded beneath the Bowman's layer and into anterior stroma in the other case diagnosed as OSSC (black dashed arrows).