Impression Cytology's Reliability as an Effective Method for Ophthalmic Neoplasm Detection

Abstract

Background:

The current investigation was intended to evaluate the precision of impression cytology and tissue histology in the detection of ocular surface neoplasia.

Materials and Methods:

We examined the histories of patients detected with ocular surface neoplasia at the Department of Ophthalmology, Kalinga Institute of Medical Sciences, Bhubaneswar. All the patients had their impressions cytology and tissue samples taken. The outcomes of both strategies were compared.

Results:

There were a total of 55 patients (33 males and 22 females) aged 12–99 years (average age, 51 years). Twenty patients had injuries to the right eye and 35 had injuries to the left eye. Conjunctival–corneal intraepithelial neoplasia (38.2%), squamous cell carcinoma (34.5%), squamous epithelium (10.9%), squamous papilloma (7.3%), conjunctival nevi (7.3%), Along with the most common histological research, malignant melanoma (1.8%). Compared with the histological results, impression cytology showed positive and negative assessment accuracies of 97.4% and 52.9%, respectively. In squamous neoplasms, squamous cell carcinoma exhibited a strong link with histology. The occurrence of dysplastic cells raised suspicion of malignancy.

Conclusion:

Because of its increased accuracy in detecting lesions, along with tissue histology, impression cytology exhibits enormous potential in identifying ocular surface neoplasia. However, impression cytology has an undesirable prognostic accuracy, indicating that it is a useful screening tool but cannot be considered as a “gold standard.”

INTRODUCTION

Ocular surface neoplasms encompass a broad and diverse range of disorders that are classified according to the source of the mass. Squamous papillomas, conjunctival–corneal intraepithelial neoplasia, and squamous cell carcinomas (SCCs) are examples of nonmelanocytic cancers that begin in the squamous epithelium, besides melanocytic lesions including nevi, primary acquired melanomas, and malignant melanomas. All these cases ought to be ruled out for malignancy situations involving fast growth, color variation, and also chronic inflammation. For the reason that a detection cannot be determined just on the basis of clinical appearance, all potentially malignant lesions should be subjected to a tissue sample. Impression cytology (IC) is a technology that collects cells from the exterior layers of the eye surface using assembling devices. It is a straightforward and a noninvasive approach to both detect and follow-up patients subsequent to the treatment of a variety of eye surface problems. The usage of IC in ophthalmology for ocular surface diseases was first published in English literature in 1977 by Thatcher et al.[1], Shields et al.[2] and also Egbert et al.[3] IC has been used to investigate dry eye disease, psoriasis conjunctivitis, vitamin A deficiency, limbal stem cell malfunction, microscopic invasion of the ocular surface, consequences of various drugs, along with ocular surface neoplasia. The main advantages of IC[1,2,3,4,5,6,7,8,9,10,11,12,13] are that it permits the assemblage of epithelial specimens that cause less discomfort to the patient, which is performed as an outpatient procedure, and also, it is more precise to the area being examined. It allows localization. Moreover, cell-to-cell interactions could be evaluated, allowing cells to be observed in their natural environment. The goal of this study was to see how accurate IC was at diagnosing ocular surface neoplasia (OSN) when compared to tissue histology.

MATERIALS AND METHODS

Before beginning this investigation, we received consent from the research ethical committee of the Department of Ophthalmology, Kalinga Institute of Medical Sciences, Bhubaneswar. Retrospective case scrutiny was conducted on every single patient with alleged ocular surface cancer. Because IC was not considered the “gold standard” for the detection, patients underwent IC simultaneously along with tissue biopsy. From the medical records, we collected the clinical information. The IC was demonstrated using a system adopted from Tseng:[4] a cellulose acetate filter having a pore size of 0.45 mm was cut into small strips with angled ends. Subsequently, topical 0.4% oxybuprocaine was applied to the eye and a strip was placed on the surface of the eye. Using the blunt edge of the forceps, we gently applied light pressure along with pulling the strip gently from the epithelial surface. We cleaned the filter paper in the jelly and used permount to mount it to the cover slip. We obtained pathological samples from the lesions by performing an incision or excisional biopsy in the IC or within the same session within 1 month. Impressions were gained in a fluid, global, diffused way. We masked both people to the opposite outcomes.

Using the Bethesda method modified in gynecology, we divided scalp cell abnormalities into four groups: (1) atypical squamous cells (ASCs); (2) low-level scaly intraepithelial lesions (LSILs), including scaly papillomas along with moderate dysplasia; (3) high-grade squamous intraepithelial lesions (HSILs), including squamous papillomas along with mild dysplasia; and (4) low-grade dysplasia when the identified cells had a HSIL nucleus and hyperchromasia, along with abnormal appearance of the nuclear membrane with a high nuclear/cytoplasmic ratio. Aggressive SCC indicates the occurrence of cellular smears along with syncytial coating and nucleoli along with intraepithelial infiltration. We examined the results of cytology along with histology samples, especially in cases of ocular scaly neoplasia (OSSN). This is not a case–control study because the researchers used positive along with negative assessment accuracy to assess it.

RESULTS

A total of 57 patients with suspected OSN were enrolled. We had to rule out two of them due to insufficient cytologic specimens. On histology, one was diagnosed as malignant melanoma. We ruled out the other patient since the IC along with histology results first indicated chronic inflammation, but a second biopsy revealed SCC. The inclusion criteria were met by 55 patients. There were 33 males and 22 females, with age ranging from 12 to 99 years (mean, 51.09 years). Twenty individuals had lesions in their right eye, whereas 35 patients had lesions in their left eye. The lesions impacted the limbus in all but one patient, and 14 (25%) of the cases had human immunodeficiency virus (HIV) infection. The demographic features of the patients, their clinical findings, along with detection based on histologic and cytologic results were all documented. SCC (20), dysplasia (20), squamous papilloma (4), and nondysplastic alterations of the epithelia were among the 50 cases diagnosed by histology (6). There were five cases of pigmented lesions, including four cases of nevus along with one case of malignant melanoma. Ten cases were classified as normal epithelia, seven as nondysplastic epithelia, one as papilloma, 24 as dysplasia, 12 as SCCs, along with one as malignant melanoma based on cytology. IC had a positive and negative predictive accuracy of 97.37% (37/38) and 52.94% (9/17), respectively, when compared to histology. The rate of false positives was 10% (1/10) and the rate of false negatives was 17.77% (8/45) [Table 1]. When we compared the cytology results to the histologic outcomes for patients diagnosed with squamous neoplasia, the biggest category in this series, SCC from cytology, had the highest rate of association with histology (91.67%), followed by HSILs (45.5%), ASCs (42.9%), normal (33.3%), and LSILs (21.4%) [Table 2]. In all but one case, the cytology specimens described as SCC, HSIL, and LSIL, which represented dysplastic alterations, corresponded with subsequent histologic reports as squamous dysplasia or SCC. This patient (case 51) had HIV seropositivity. We detected SCC based on cytology, but histology, for which we obtained samples by an incisional biopsy, revealed only hyperkeratotic cells. This patient refused a second biopsy, and the lesion eventually resolved with topical mitomycin C therapy.

Table 1.

Relationship between IC and tissue histology

Histology
Malignancy/preinvasive benign
Cytology	Lesions	Lesions	Total (n)
Dysplastic findings	37	1	38
Nondysplastic findings	8	9	17
Total (n)	45	10	55

IC=impression cytology

Table 2.

Correlation of cytology and histology findings for types of squamous epithelial lesions (n=50)

Histology (n)
Cytology (n)	SCC	HSIL	LSIL	ASC	Normal	Total
SCC	11 (91.7%)	0	0	1	0	12
HSIL	5	5 (45.5%)	1	0	0	11
LSIL	1	10	3 (21.4%)	0	0	14
ASC	2	1	3	3 (42.9%)	0	7
Normal	1	2	1	0	2 (33.3%)	6
Total	20	18	6	4	2	50

HSIL=high-grade squamous intraepithelial lesion, LSIL=low-level scaly intraepithelial lesion, SCC=squamous cell carcinoma

DISCUSSION

It is critical to differentiate benign, preinvasive, and invasive lesions in the treatment of ocular surface neoplasia. However, repeated biopsies to follow-up suspicious lesions might result in scarring, lid deformity, limbal insufficiency, along with discomfort for the patient. IC is a system where a specimen is obtained by gently placing cellulose acetate filter paper sheets against the ocular surface. The key benefits are that it makes collecting epithelial samples very simple and it is painless for patients, as well as allows for more exact site of the expanse being examined. In 1994, Nolan et al.[10] testified that IC was efficacious in diagnosing conjunctival neoplasms, showing good outcomes in 77% of patients. The Papanicolaou method was employed to stain the samples, which were obtained using cellulose acetate filter paper. Later, Tole et al.[11] used a Biopore membrane device to study the usage of IC in OSSN and found an upsurge in prediction proportion in 80% of cases verified histologically. The conservation of limbal stem cells, which are found in the basal layer of the limbal epithelium and are responsible for corneal epithelial renewal throughout life, is another benefit of IC. In the majority of instances of OSSN, the lesions primarily affect the limbus and are prone to recurrence. When compared to recurrent biopsies, IC is a safer method of detection. Furthermore, IC can be utilized in the posttreatment follow-up of patients to assess disease recurrence as well as the effects of treatments like topical chemotherapy.

IC had been used to predict the histologic diagnosis of melanocyte tumors by detecting atypical melanocyte. In pigmented lesions, IC had a prediction rate of 73%. The adherence of atypical melanocytes to the surface of the conjunctival epithelium, they said, was a sign of malignancy. In this investigation, a few melanocytic lesions were also looked at, and the outcomes of both IC and tissue histology matched in those cases. The thickness of the filter paper makes it harder to focus during cytologic feature assessment, which is another disadvantage of this procedure. As a result, interpreting IC specimens requires the expertise of a trained and experienced cytologist. The fallouts of this trial show that in comparison to tissue histology, IC has a high positive-predictive accuracy in diagnosing OSN. The occurrence of dysplastic cells in cytology specimens indicates malignancy; also, the cytology findings can be classified to assist in predicting histology outcomes.

CONCLUSION

We established the accuracy of IC that can be utilized as an alternative to surgery in the detection of ocular surface cancer. However, this method has drawbacks, especially in keratotic lesions where surface keratin might obstruct impression sampling. In circumstances where the cytology is negative, a tissue biopsy is still required.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.