|Year : 2017 | Volume
| Issue : 3 | Page : 190-194
Study to correlate clinical and histopathological characteristics of pterygium in predicting its recurrence
Iqra Mushtaq1, Renu Magdum1, Archana Buch2, Banyameen Mohamad Iqbal2, Spriha Arun1, Jyotsna Malhotra1
1 Department of Ophthalmology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pune, Maharashtra, India
2 Department of Pathology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pune, Maharashtra, India
|Date of Web Publication||17-Aug-2017|
Banyameen Mohamad Iqbal
Department of Pathology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune - 411 018, Maharashtra
Source of Support: None, Conflict of Interest: None
Background: Pterygium is a fleshy, triangular, or wing-shaped growth of the conjunctiva that encroaches onto the cornea. It is an active, invasive, inflammatory process associated with cellular proliferation, connective tissue remodeling, and angiogenesis.
Materials and Methods: It is a prospective 2-year study. One hundred eyes with pterygium presenting in ophthalmology department in a tertiary care hospital in Western Maharashtra, India, were selected. Clinical and histopathological characteristics of pterygia were noted. Statistical analysis of the obtained results was carried out by a statistical program package (SPSS, version 15 and Epi Info, version 7).
Results: Out of 100 pterygia, 93% were nasally located, 17% were seen in bilateral eyes, 91% of the pterygia were ≤4 mm in size, and 75% were progressive in nature. Stocker's line was seen in 25% of cases whereas Fuchs spots were seen in only 4% of cases. Thirty-four percent of pterygia were having Grade 1 inflammation whereas 18% were having Grade 0 and Grade IV inflammation each. Similarly 36% pterygia were showing grade II vascularization and 35% were showing grade III fibrinoid necrosis. A total number of pterygia that recurred in our study (n = 3) were showing high grades of inflammation, vascularization, and fibrinoid change (Grade IV each).
Conclusion: All the pterygia were surgically removed with conjunctival autograft technique, and the pterygia which recurred in our study (n = 3) were all nasally located, progressive in nature, and > 4 mm in size with positive Fuchs spots and negative Stocker's line. All were showing high-grade (Grade IV) inflammation, vascularization, and fibrinoid change.
Keywords: Autograft, pterygium, pterygium histology
|How to cite this article:|
Mushtaq I, Magdum R, Buch A, Iqbal BM, Arun S, Malhotra J. Study to correlate clinical and histopathological characteristics of pterygium in predicting its recurrence. J Med Soc 2017;31:190-4
|How to cite this URL:|
Mushtaq I, Magdum R, Buch A, Iqbal BM, Arun S, Malhotra J. Study to correlate clinical and histopathological characteristics of pterygium in predicting its recurrence. J Med Soc [serial online] 2017 [cited 2020 Feb 28];31:190-4. Available from: http://www.jmedsoc.org/text.asp?2017/31/3/190/207668
| Introduction|| |
Pterygium has been described as an ophthalmic enigma as much is still not known about this common condition. The name “Pterygium” comes from the Greek word “Pterygos” which means “wing.” Pterygium is a triangular degenerative condition of the subconjunctival tissue which undergoes elastotic degeneration and then proliferates as a granulation tissue which is vascularized to invade the cornea, destroying the superficial layers of stroma and Bowman's membrane. Its incidence is more in tropical and subtropical regions between 30° latitude North and South of the equator. The prevalence varies geographically with rates as high as 29% in certain equatorial areas. The incidence of pterygium in India is on an average 5.2% (ranging from 0.075% in Punjab to 10.42% in Maharashtra). The major predisposing factors are the hot and dry climate and long periods of ultraviolet light exposure. Macroscopically, pterygium consists of a head, a cap toward the advancing edge, and the body lying limbal to the head. Microscopically, pterygia shows loose fibrous connective tissue, replacement of Bowman's membrane by collagen, lymphocytic infiltration, and plasma cells accompanied with angiogenesis and fibrosis. Definitive treatment of pterygium is surgery. Recurrence of the pterygium after surgical excision is the single most common cause of failure of pterygium surgery. Reported rates of recurrence vary widely from 0% to 89%. The rate of recurrence of pterygium is broadly dependent on various factors such as clinical features, histopathological grading, and the type of surgery performed.
| Materials and Methods|| |
This is a prospective interventional study carried out for a period of 2 years ranging from September 2013 to August 2015 on 100 eyes with pterygium, presenting in ophthalmology outpatient department, in a tertiary care hospital in Western Maharashtra, India. Ethical Committee approval for conducting the study was taken. Patients with pterygium undergoing surgery for decreased visual acuity and/or cosmetic reasons were included in this study; however, patients having pseudopterygium and/or coexisting conjunctival diseases were excluded from the study. Clinical parameters studied were: site of pterygium (nasal/temporal), size of pterygium (measured from limbus to cornea), laterality (unilateral/bilateral), type of pterygium (atrophic/progressive), presence of Stocker's line, and presence of Fuchs spots. Informed written consent was obtained on the previous day of the surgery, and patients were explained regarding complications of surgery and anesthesia. All the pterygia were excised by conjunctival autograft technique, and the patients were followed postoperatively for 6 months to check for any recurrence. All the pterygium specimens were duly processed and immediately placed in 10% formalin before sending for histopathology examination. In histopathology laboratory, 3–5 μ thick paraffin-embedded sections were cut using a microtome, and the sections so formed were stained by classic histochemical stains: hematoxylin and Eosin; Masson's trichrome; Gomori's reticulin; and periodic acid–Schiff stains. Histopathological parameters were classified into three groups - inflammation intensity, degree of vascularization, and degree of fibrinoid change, which was in turn divided into five groups each ranging from 0 to 4 depending on the intensity of the lesion. The clinical and histopathological characteristics of pterygia were noted. The results of histopathological and clinical characteristics of pterygium were comparatively analyzed. Statistical analysis of the obtained results was carried out by a statistical program package (Statistical Package for Social Science, SPSS software, version 15, SPSS Inc and Epi Info, version 7, CDC Atlanta, USA). Analytical tests which were done included calculated probability (P value), Chi-square test for linear trend, Fisher's exact test, and tables containing data distribution. Follow-up of the patients was done after 3 and 6 months.
| Results|| |
Out of 100 pterygia, 93% were nasally located and only 7% were located temporally. Eighty-three percent of the total pterygia were found in unilateral eyes whereas only 17% were seen in bilateral eyes. Depending on the size of the pterygia, we found 91% of pterygia to be ≤4 mm in size as compared to only 9% which were >4 mm in size. A maximum number of pterygia, 75%, were progressive in nature whereas only 25% were atrophic. Another important finding in our study was the presence of Stocker's line, which was present in 25% on the cases. All the pterygia in which Stocker's line was present were atrophic in nature. Fuchs spot was seen in only 4% of all the pterygia.
On microscopic examination, we found 34% of pterygia having Grade 1 inflammation whereas 18% were having Grade 0 and Grade IV inflammation each. Similarly 36% pterygia were showing grade II vascularization and 35% were showing grade III fibrinoid necrosis [Figure 1].
Out of all the pterygia which were >4 mm in size (n = 9), 100% were showing Grade IV inflammation, 78% were showing Grade IV vascularization, and 78% were showing Grade IV fibrinoid change.
Depending on the type of pterygium (progressive or atrophic), the microscopic features were showing a linear trend with increased grades in progressive pterygium as compared to atrophic [Table 1]. The trend is statistically significant.
|Table 1: Relationship of type of pterygia with its histological features|
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Relationship between histopathological features and Stocker's line also shows a linear trend. All the pterygia in which Stocker's line is present (n = 25) show minimum degree of inflammation, vascularization, and fibrinoid change [Table 2]. The relationship was statistically significant.
|Table 2: Relationship between stocker's line and histopathological features|
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The presence of Fuchs spots (n = 4) is related to high degrees of inflammation, vascularization, and fibrinoid change. We have seen 75% (n = 3) of Fuchs spots present in pterygium having Grade IV inflammation, vascularization, and fibrinoid change.
On comparing clinical and histopathological features of pterygium, we deduced that the total number of pterygium that recurred in our study (n = 3) between a period of 3–6 months was showing high grades of inflammation, vascularization, and fibrinoid change (Grade IV in all). All of them were nasally located, all were progressive in nature, and all were >4 mm in size with positive Fuchs spots and negative Stocker's line [Table 3].
|Table 3: Comparison of clinicopathological features of recurrent pterygium|
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| Discussion|| |
Pterygium is more frequently located nasally than temporally. In our study, 93% of pterygia were located nasally whereas only 7% were temporal. Almost same findings have been reported by Lin et al., which showed that 98.68% of the study group had pterygium located on the nasal side. Another study done by Meseret et al. showed that 92% of the study group has nasal pterygium whereas 4.5% had temporal pterygium. The hypothesis explaining this location-wise distribution of pterygia describes that the bulbar conjunctiva temporal to the cornea is situated below the lacrimal gland and may be less prone to drying as it is bathed by fresh tears, hence the relative rarity of pterygium in the temporal position. Pterygium location has also been explained by noting that the longer temporal eyelashes of the upper eyelid and the greater downward “bowing” of the outer two-thirds of the upper eyelid shade and filter light falling on the temporal (compared with the nasal) conjunctiva and cornea., The nasal bulbar conjunctiva is also more exposed to sunshine as eyebrow hair is shorter nasally than temporally.
Size of the pterygia plays a major role in its recurrence. The smaller the pterygia the less are its chances of recurrence after surgery. In our study group, 91% (n = 91) were having pterygia <4 mm extending onto the cornea whereas 9% (n = 9) were having pterygia of size >4 mm extending onto the cornea. Our study is in accordance with the study done by Meseret et al. on 81 patients having pterygia in which 90.7% of patients were having extent of pterygia in the range of < 4 mm onto the cornea.
Incidence of progressive pterygium in our study was 75% whereas atrophic pterygium was only 25%; it is almost comparable to the study done by Krishnaram on 115 rural patients, in which he found the incidence of progressive pterygium to be 68% whereas atrophic pterygia to be 32%. This slight variation can be attributed to geographical variation and the selection of study group.
Our study showed four patients to be positive for Fuchs spots, out of which three showed recurrence (75%) in a period ranging from 3 to 6 months. One patient positive for Fuchs spot did not show any recurrence (25%). The results of our study can be compared exactly to the study of Džunic et al. in which out of eight patients found to be positive for Fuchs spots, 6 (75%) showed recurrence in a period extending up to 6 months.
In our study, 25% of cases showed Stocker's line formation and all of those cases turned out to be of atrophic pterygia. Cilova-Atanasova in their study described the presence of Stocker's line as significant as it determines the nature of pterygium to be progressive or atrophic.
In our study, we have found that as the size of the pterygium increases, the degree of inflammation also increases. All nine out of nine pterygia (100%) which were >4 mm in size show Grade IV inflammation, whereas in pterygia which were <4 mm in size, the maximum number, that is, 37% were showing Grade I inflammation. It should be noted here that as the size of the pterygium increases (progressive pterygium), there is also an increase in the degree of vascularization as well as fibrinoid change. Fisher's exact test was applied (P < 0.0001) which was statistically significant. It is further noted that in our study, all the cases which recurred were having Grade IV Inflammation, vascularization, and fibrinoid change. The studies of Džunic et al. and Cilova-Atanasova have also shown a positive relationship between the size of pterygium and its histological features such as inflammation, vascularization, and fibrinoid change. They also mentioned that as the degree of histological features increases, there is an increased chance of recurrence after surgery.
Other features responsible for increased rate of recurrence are the surgical techniques used for pterygium surgery. In our study, we used the same surgical technique of “conjunctival autograft” for all the patients operated. In a study done on 118 pterygia done by Khan et al., the rate of recurrence varied from 7% to 36%. They had employed conjunctival autograft surgical technique and bare sclera technique, respectively. The reason for less recurrence rate in our study may be because of less time of follow-up (6 months) and most importantly the surgical technique used by us, that is, conjunctival autograft, which has been shown to have lowest rates of recurrence (2%) by a study done by Kwok and Coroneo.
In a recent study done by Nuhoglu et al., they concluded that there is an association between the histology of pterygium and recurrence rate, however they are not statistically significant. Our study also found an association between the histology of pterygium and recurrence rate, however it is not statistically significant.
| Conclusion|| |
To conclude, recurrence is the main problem for a pterygium surgery. The reasons for pterygium recurrence are multifactorial and vary from clinical to pathological. The clinical and pathological features of the pterygia which recurred in our study (3%) all were nasally located and were > 4mm in size encroaching onto the cornea. All the pterygia were progressive and were positive for Fuch's spots. All the recurred pterygia were showing high grades (Grade IV) of inflammation, vascularisation and fibrinoid change. The clinical and histological features of pterygia although closely associated with recurrence were not found to be statistically significant.
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[Table 1], [Table 2], [Table 3]