Indian Journal of Ophthalmology

ARTICLES
Year
: 1976  |  Volume : 24  |  Issue : 2  |  Page : 16--18

Pinguecula and pterygium (a histopathological study)


IN Raizada, NK Bhatnagar 
 L.L.R.M., Medical College, Meerut, India

Correspondence Address:
I N Raizada
L.L.R.M., Medical College, Meerut
India




How to cite this article:
Raizada I N, Bhatnagar N K. Pinguecula and pterygium (a histopathological study).Indian J Ophthalmol 1976;24:16-18


How to cite this URL:
Raizada I N, Bhatnagar N K. Pinguecula and pterygium (a histopathological study). Indian J Ophthalmol [serial online] 1976 [cited 2022 May 17 ];24:16-18
Available from: https://www.ijo.in/text.asp?1976/24/2/16/31527


Full Text

The histopathology of pinguicula and pterygium was so very thoroughly studied by Fuchs[6] that very little has been added to their basic knowledge since his da\s. He concluded that the histopathology of pingue­cula is characterized by increased number of thickened elastic fibres, hyaline degeneration of the conjunctival tissue, concretions and epithe­lial changes and that similar changes also occur in pterygium along with characteristic corneal involvement

In an earlier study, Raizada et al[12] reported on the histopathology of pterygium. The find­ings were grouped in three phases, i.e. a proliferative phase, a fibromatous phase and an atrophic sclerotic phase. The present study was undertaken to find out if the histopathology of pinguecula resembles in any way with any phase of pterygium, reported by us earlier.[12]

 Material and Methods



This histopathological study has been carried out in ten specimens of pinguecula obtained in a random way from patients who attended the outpatient departments at Medical Colleges in Kanpur and Meerut, India, for pterygium in one eye and pinguecula in the other. The specimens were blocked, sectioned and stained with haematoxylin and eosin stain, Modified Mayer's method (for amyloid degeneration) and Verhoeff's stain (for elastic fibres). The results were compared with the pterygium study published earlier.

 Observations



(i) Epithelium was single layered or two or three layered thick acquiring strati­fied nature. [Figure 1]

(ii) Major portion of the section contained horizontally placed fibro-elastic tissue which had curly appearance. [Figure 2] Fibroblasts lined the walls of newly formed blood vessels. [Figure 5]

(iii) Areas of hyaline and amyloid degene­ration scattered here and there. [Figure 3],[Figure 4].

(iv) Round cell infiltration though present was not a prominent feature.

 Discussion



The histopathology of pterygium has been grouped by Raizada et al[12] in three phases i.e. proliferative phase, fibromatous phase and atrophic sclerotic phase. The fibromat­ous phase was observed in 52% of pterygia studied. The salient features of this phase were-flattening of the epithelial cells and nuclei showing a tendency to scar formation or having actually converted into a scar, fibroblas­tic activity and fibrous tissue formation, round cell infiltration, plasma cell sprinkling and neovascularization while on the other hand, atrophic sclerotic phase observed in 18% of the cases studied was characterized by pro­nounced atrophy and sclerosis of the epithe­lium, hyaline degeneration, amyloid degenera­tion, calcium deposits, fibroblastic activity and fibrous tissue formation. Similar views have been expressed by Kamel3 and Gerundo[11]

From the observations, it is clear that the histopathology of pinguecula resembles in many respects the late fibrotic or early atrophic sclerotic phase of pterygium. That both ptery­gium and pinguecula occur in the interpalpebral zone (a zone of epithelial change) and that their histopathology is similar in many respects make us believe that they represent a kindred reaction to similar stimuli. Sugar[14] believes that pinguecula is carried on to the cornea as the head of the pterygium and may leave no evidence of its original position.

But it must be mentioned that every pingue­cula does not invariably become a pterygium. We believe that there is a potential limbal barrier which normally does not allow a pin­guecula to advance over the cornea. When this potential limbal barrier is crossed, pingue­cula advances over the cornea.

If one disregards the corneal changes then the histopathology of pinguecula and pterygium is identical in our series of cases. On this basis we can say that pinguecula is a precursor of pterygium, a view which has been disputed by Schoninger[13] Friede,[5] Almeida Reboucas[1] and Forius and Erikson[4] but supported by others. Evidence exists in literature that ultra­violet rays in solar radiations may produce corneal changes[10]. Solar radiations supplement­ed in many cases by dry and dusty conditions[2],[3] may help in breaking of the limbal barrier and the encroachment of the pinguecula over the cornea.

 Summary



Ten pinguecula were subjected to histopa­thological study, using haematoxylin and eosin stain, Verhoeff's stain and modified Mayer's method for amyloid degeneration. The histo­pathology resembled the late fibrotic or early sclerotic please of pterygium. On the basis of the above study we conclude that pinguecula is a precursor of pterygium[15].

References

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