Benign epibulbar tumours
Conjunctival naevus
Diagnosis
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Presentation: in 1st and 2nd decades.
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Signs: (a) slightly elevated pigmented bulbar lesion of variable size and pigmentation, (b) often juxtalimbal ( Fig. 20.1A ), (c) cystic spaces are common ( Fig. 20.1B ).
Fig. 20.1
Conjunctival naevus: (A) juxtalimbal, (B) showing cystic changes.
(From Salmon JF, Kanski’s Clinical Ophthalmology: A Systematic Approach , 9th edition. Oxford, UK: Elsevier; 2020.)
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Signs of potential malignancy: (a) prominent feeder vessels, (b) sudden growth or increase in pigmentation, (c) development after the 2nd decade, particularly in an unusual site such as palpebral or forniceal conjunctiva.
Treatment
excision, usually for cosmetic reasons; less commonly for irritation or suspicion of malignancy.
Conjunctival papilloma
Pathogenesis:
often infection with human papillomavirus (especially types 6 and 11), particularly in childhood.
Diagnosis:
(a) solitary pedunculated or sessile lesion, (b) most frequently juxtalimbal in the fornix ( Fig. 20.2A ) or caruncle, (c) may occasionally be multiple and confluent.
Treatment:
small lesions often resolve spontaneously. Large papillomas may require excision, sometimes with cryotherapy to the base and surrounding area.
Dermoid
Histology:
solid mass of collagenous tissue containing dermal elements covered by stratified squamous epithelium.
Diagnosis
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Presentation: in early childhood.
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Signs: (a) smooth yellowish subconjunctival mass of soft consistency, (b) most frequently at the inferotemporal limbus, (c) protruding hair may be seen ( Fig. 20.2B ).
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Systemic associations: Goldenhar syndrome (oculoauriculovertebral spectrum) and less commonly, Treacher Collins syndrome.
Treatment:
small lesions are excised; large dermoids may require lamellar keratosclerectomy.
Dermolipoma
Histology:
similar to solid dermoid, but also contains fatty tissue.
Diagnosis
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Presentation: adulthood
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Signs: (a) soft yellowish subconjunctival mass near the outer canthus ( Fig. 20.3A ), (b) keratinized surface; may exhibit hairs
Fig. 20.3
(A) Dermolipoma, (B) pyogenic granuloma after pterygium surgery.
(From Salmon JF, Kanski’s Clinical Ophthalmology: A Systematic Approach , 9th edition. Oxford, UK: Elsevier; 2020.)
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Treatment: usually avoided, but in selected cases anterior debulking procedure (beware: lacrimal gland lobe)
Pyogenic granuloma
Pathogenesis:
fibrovascular proliferation in response to a conjunctival insult such as surgery, trauma, or ruptured chalazion; spontaneous lesions are rare.
Diagnosis
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Presentation: usually a few weeks after surgery, with a fast-growing, pink, fleshy, vascularized conjunctival mass, near a wound ( Fig. 20.3B ).
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Differential diagnosis: (a) suture granuloma, (b) vascular tumour, (c) Tenon granuloma or cyst.
Treatment:
topical steroids; excision of persistent granuloma.
Conjunctival (racial) epithelial melanosis
Definition:
very common in dark-skinned individuals. Both eyes are affected, often asymmetrically.
Diagnosis:
(a) areas of flat, patchy, brownish pigmentation scattered throughout the conjunctiva, (b) more intensely at the limbus and around perforating vessels or nerves as they enter the sclera (Axenfeld loop; Fig. 20.4A ), (c) the pigment lies within the epithelium and therefore moves freely over the surface of the globe.
Malignant and premalignant epibulbar tumours
Primary acquired melanosis (PAM)
Definition:
unilateral condition typically affecting white individuals older than 45 years of age. There are two histological variants which cannot be distinguished clinically:
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PAM without atypia: no risk of malignant transformation.
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PAM with atypia: regarded as melanoma in situ ; has a 50% chance of infiltrative malignancy within 5 years.
Diagnosis
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Signs: (a) irregular solitary or multifocal areas of flat, golden brown to dark chocolate epithelial pigmentation, (b) seen most commonly in the interpalpebral region, although any part of the conjunctiva may be affected ( Fig. 20.4B ).
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Course: (a) PAM may expand, shrink, or remain stable for long periods, (b) may focally lighten or darken, (c) malignant transformation should be suspected if a flat lesion becomes nodular.
Treatment:
(a) small lesions may be excised, (b) large lesions should undergo incisional biopsy from various sites, with subsequent cryotherapy or topical mitomycin C for PAM with atypia.
Conjunctival melanoma
Origin:
(a) from PAM with atypia (75%), (b) pre-existing naevus (20%) or (c) de novo .
Diagnosis
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Presentation: in 6th decade.
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Signs: (a) black, grey, or pinkish (amelanotic) vascularized nodule; may be fixed to the episclera, (b) commonly at the limbus ( Fig. 20.5A ), but may develop anywhere, (c) multifocal lesions can arise from PAM with atypia as areas of thickening and nodularity ( Fig. 20.5B ).
Fig. 20.5
Conjunctival melanoma: (A) at the limbus, (B) multifocal.
(From Salmon JF, Kanski’s Clinical Ophthalmology: A Systematic Approach , 9th edition. Oxford, UK: Elsevier; 2020.)
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Poor prognostic indicators: (a) multifocal tumour, (b) forniceal location, (c) thickness of 2 mm or more. Mortality at 10 years is 25%.
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Differential diagnosis: (a) large naevus, (b) ciliary body melanoma with extraocular extension, (c) pigmented conjunctival carcinoma.
Treatment:
excision with a wide-margin lamellar scleroconjunctivectomy and cryotherapy; radiotherapy to the base if deep extension is present histologically.
Ocular surface squamous neoplasia
Definition:
spectrum of benign, premalignant and malignant unilateral, slowly progressive epithelial lesions of the conjunctiva and cornea.
Risk factors:
(a) excessive ultraviolet exposure, (b) human papilloma virus infection, (c) AIDS, (d) xeroderma pigmentosum, (e) smoking.
Diagnosis
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Presentation: in old age with irritation or a visible mass within the interpalpebral fissure; commonly juxtalimbal, but may involve any part of the conjunctiva or cornea. Male preponderance in Europe and the USA; female in sub-Saharan Africa.
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Signs: variable and limited correlation with histological type: (a) gelatinous mass with superficial vessels ( Fig. 20.6A ), (b) elevated white leucoplakic plaque, (c) fleshy pink papillomatous lesion with prominent feeder and surface blood vessels, (d) can masquerade as chronic conjunctivitis, (e) corneal involvement may occur ( Fig. 20.6B ).
Fig. 20.6
Squamous carcinoma: (A) limbal, with dysplastic epithelium, (B) gelatinous lesion extending onto cornea.
(From Salmon JF, Kanski’s Clinical Ophthalmology: A Systematic Approach , 9th edition. Oxford, UK: Elsevier; 2020.)
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Spread: intraocular extension is uncommon and metastatic disease is rare.
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Investigations: ultrasonic biomicroscopy (UBM) to estimate the depth of invasion, and impression cytology.
Treatment:
(a) Excision with 2- or 3-mm margins and assessment of clearance with frozen sections. Take care not to excise below Bowman membrane, as recurrent disease can then penetrate the corneal stroma. (b) Adjunctive measures aimed at reducing recurrence include cryotherapy, brachytherapy and topical chemotherapy. (c) Topical interferon alpha-2b is particularly effective, leading to complete resolution in 80% of patients. In the immune-compromised, a once daily instillation should be used lifelong to prevent recurrence.
Lymphoproliferative lesions
Pathology:
most conjunctival lymphoproliferative lesions consist of reactive lymphoid hyperplasia, but lymphoma may arise de novo , by extension from orbital disease or occasionally associated with systemic involvement. Rarely, reactive hyperplasia undergoes malignant transformation. Most conjunctival lymphomas are of B cell origin.
Diagnosis
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Presentation: in the 7th and 8th decades with irritation or painless swelling; may be bilateral.
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Signs: slow-growing salmon-pink or flesh-coloured mobile infiltrate ( Fig. 20.7A ).
Fig. 20.7
(A) Conjunctival lymphoma, (B) Kaposi sarcoma.
( Figure 20.7B courtesy of T. Carmichael.)
Treatment:
radiotherapy, chemotherapy and excision.
Kaposi sarcoma
Definition:
slowly growing vascular tumour ( Fig. 20.7B ) occurring almost exclusively in individuals with AIDS.
Diagnosis:
in the early stages presents as a flat bright-red lesion that may mimic a subconjunctival haemorrhage.
Treatment:
radiotherapy or excision, with or without adjunctive cryotherapy.
Iris tumours
Iris naevus
Diagnosis
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Signs: (a) solitary pigmented, flat or slightly elevated, circumscribed lesion usually less than 3 mm in diameter, (b) typically located inferiorly ( Fig. 20.8A ).
Fig. 20.8
Iris tumours: (A) naevus, (B) melanoma, (C) melanoma with pupillary distortion, (D) melanoma with angle invasion.
( Figure. 20.8D courtesy of B. Damato.)
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Signs of potential malignancy: (a) prominent vascularity, (b) rapid growth, (c) diffuse spread, (d) seeding.
Treatment:
not required, although observation is sometimes indicated.
Iris melanoma
Pathology:
approximately 8% of uveal melanomas arise in the iris. The majority are composed of spindle cells of low-grade malignancy. Predisposing factors include: (a) fair skin, (b) light iris colour, (c) numerous cutaneous naevi, (d) congenital ocular and oculodermal melanocytosis (naevus of Ota), (e) NF1.
Diagnosis
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Presentation: in 5th and 6th decades with enlargement of a pre-existing iris lesion.
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Typical signs: (a) very slowly growing pigmented or nonpigmented nodule at least 3 mm in diameter, (b) usually in the inferior half of the iris ( Fig. 20.8B ), (c) often associated with surface blood vessels.
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Associated signs: (a) pupillary distortion ( Fig. 20.8C ), (b) ectropion uveae, (c) angle invasion ( Fig. 20.8D ) with glaucoma, (d) localized cataract.
Treatment:
(a) observation of suspicious lesions, (b) iridectomy for small tumours and iridocyclectomy for angle invasion, (c) brachytherapy or external proton beam irradiation, (d) enucleation for diffusely growing tumours if radiotherapy is not possible.
Iris cysts
Primary
Diagnosis
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Signs: unilateral or bilateral, solitary or multiple globular brown ( Fig. 20.9A ) or transparent structures located at the pupillary border, midzone or iris root.
Fig. 20.9
Iris cyst: (A) primary, (B) implantation.
( Figure 20.9A courtesy of R. Bates.)
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