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Keloids are usually formed in individuals after skin trauma and are thought to be the result of altered wound healing with excessive scar tissue formation.1 We describe a bulbar conjunctival keloid confirmed by immunohistochemical analysis and scanning electron microscopy.
A 48‐year‐old Hispanic man presented with a medial conjunctival lesion in his left eye. The patient had underwent pterygium surgery in the same location 2 years previously. At 6 months after surgery, he noted progressive growth of a conjunctival mass that persisted over the next year. On examination, his vision was 20/25 in the right eye and 20/30 in the left eye. Slit‐lamp examination revealed a 5 mm×10 mm firm, peduncular conjunctival mass in the left medial bulbar conjunctival region (fig 1A1A).). There were several prominent blood vessels on its surface. Clinical impression was a conjunctival malignant neoplasm.
The patient underwent en bloc surgical resection, without violation of the capsule, and the lesion was sent for histopathological examination. Microscopically, the conjunctival mass revealed exuberant deposits of collagen fibres in the stroma, thickened and closely packed with hyalinisation and a paucity of cellular deposits (fig 1B1B).). Collagen fibres stained positive for Masson's trichrome (fig 1C1C),), and negative for CD 34 antigens and were minimally positive for α‐smooth muscle actin antigen. Scanning electron microscopy revealed random orientation of haphazardly connected collagen bundles to epithelial surface (fig 1D1D),), which are considered typical for keloid.2 At 1 month of operation, the vision was unchanged and the conjunctiva was healed at the surgical site.
We are unaware of previous reports of conjunctival keloid and could find no reference in a computerised search using PubMed. Even though conjunctival keloids have not been reported, keloids involving cornea have been observed.1,3,4 Keloids must be differentiated from hypertrophic scars. They both involve benign fibrous growth that occurs after trauma and show no morphological differences with light microscopy. However, they require different therapeutic approaches as keloids extend beyond the original wound, rarely regress and have a high rate of recurrence after surgical excision; whereas hypertrophic scars remain within the confines of the original wound, spontaneously regress and rarely recur after excision.1,2,5
Immunohistochemical analysis and scanning electron microscopy are essential to confirm the diagnosis of keloid and differentiate it from hypertrophic scar. The presence of α‐smooth muscle actin‐expressing myofibroblasts is a feature of hypertrophic scars, whereas keloids have only few α‐smooth muscle actin‐expressing myofibroblasts.1,5 In this case, α‐smooth muscle actin antigen expression is minimal, whereas scanning electron microscopy shows typical features of keloid collagen (fig 1D1D).
The common lesions at the site of pterygium excision include pyogenic granuloma, recurrence of pterygium and squamous neoplasias. The present case indicates the occurrence of keloid as well. Clinicians should consider keloid in the differential of conjunctival mass that occurs at the site of pterygium excision.
Funding: This study was funded by the Research to Prevent Blindness, New York, USA, and NIH grant EY03040. RNK is a Heed Fellow and is supported by the Heed Ophthalmic Foundation.
Competing interests: None declared.