Abstract
Pterygium is a common lesion consisting of fleshy conjunctival growth extending towards the cornea. There is no documented risk of malignant transformation; however, concomitant disease is not rare, and its link to sunlight exposure indicates a risk of other malignancies. The purpose of our study is to describe histopathological features of resected pterygiums and to recognize patients at risk of other conjunctival diseases. One hundred and forty-nine formalin-fixed and paraffin-embedded pterygium samples were subjected to histopathological analysis. Histological H&E sections were obtained and digitalized using a Zeiss Axio Scan.Z1 slide scanner. Thirteen predefined morphological features were used to record histopathological changes in the epithelium and substantia propria. Neovascularization was observed in 54% of the samples. Sun damage, comprising solar elastosis and stromal plaque, was present in 81% of the samples. Variation in epithelial thickness was the most common change, with acanthosis and atrophy being observed in 62% and 26% of the samples, respectively. In our series, 21% (31/149) of pterygiums showed mild to moderate dysplasia, a finding that may be associated to ocular surface squamous neoplasia (OSSN). Moreover, 32% (47/149) of the cases showed melanocytic hyperplasia, which could represent primary acquired melanosis (PAM). There is a positive correlation between dysplasia and chronic inflammation (p=0.012) and an inverse correlation with epithelial atrophy (p=0.001) and neovascularization (p=0.05). Similarly, a positive correlation is observed between goblet cell hyperplasia and melanocytic hyperplasia (p=0.02). Our findings show that pterygiums harbour histological features that may be suggestive of OSSN or PAM in 53% of our patients. Whilst being on the benign side of the spectrum, these two entities are known for their potential progression to malignancy. A recommendation is made for all surgically excised pterygiums to be sent for histopathological diagnosis, and clear guidelines for reporting of these lesions should be established. Associated histopathological findings suggestive of other concomitant diseases should be identified to insure adequate follow-up of these patients.
Highlights
Pterygium is a superficial growth of loose connective tissue that is vascularized and covered by an epithelium of varying thickness
An accurate description would resemble the one from Chui et al.: “a centripetal growth of a leading edge of altered limbal epithelial cells followed by squamous metaplastic epithelium with goblet cell hyperplasia, an underlying Journal of Ophthalmology stroma of activated fibroblasts, neovascularization, inflammation, and extracellular matrix remodelling.” [1] e presence of epithelial atypia and melanocytic hyperplasia may possibly be added to this description, and one can have a complete assessment of pterygium
As both these percentages are based on a search through histopathological reports, we suspect this number to be an underrepresentation of the reality as not all excised pterygiums are sent for histopathological review, and, when they are, there is no consensus on reporting of these lesions
Summary
Pterygium is a superficial growth of loose connective tissue that is vascularized and covered by an epithelium of varying thickness. Still today, this is an accepted histopathological description for pterygium. To this definition, some may add prominent elastotic degeneration of the stroma and variable inflammatory infiltrate, all of which is often accompanied by “consistent with clinical diagnosis of pterygium.”. E issue with this, far too generic, histopathological description is that it does not tap into the deceptive side of the pterygium, the one where preneoplastic growth and atypia may be hiding. An accurate description would resemble the one from Chui et al.: “a centripetal growth of a leading edge of altered limbal epithelial cells followed by squamous metaplastic epithelium with goblet cell hyperplasia, an underlying. With growing evidence pointing towards a preneoplastic process, a shift in the clinical management of pterygia is foreseeable
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