Benign Epibulbar Tumours
Conjunctival naevus
Introduction
A conjunctival naevus is the most common melanocytic conjunctival tumour; the overall risk of malignant transformation is less than 1%. Treatment by excision is usually for cosmesis, but sometimes for irritation or a suspicion of malignancy. The histological appearance is similar to that of cutaneous naevi, but as there is no conjunctival dermis, subepithelial and stromal replace dermal in the nomenclature:
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Compound naevi are characterized by the presence of naevus cells at the epithelial–subepithelial junction and within the subepithelial stroma, often with epithelial inclusions such as cysts and goblet cells ( Fig. 12.1A ).
Fig. 12.1
Conjunctival naevus. (A) Compound naevus histology – see text; (B) junctional naevus histology – see text; (C) partially pigmented naevus; (D) cystic pigmented naevus; (E) non-pigmented naevus (F) caruncular location
(Courtesy of J Harry – fig. A; J Harry and G Misson, from Clinical Ophthalmic Pathology , Butterworth-Heinemann 2001 – fig. B; S Chen – figs D and E)
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Subepithelial lesions are confined subepithelially.
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Junctional naevi consist of nests of naevus cells at the epithelial–subepithelial junction ( Fig. 12.1B ). They are uncommon.
Clinical features
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Symptoms. The lesion is typically initially noticed in the first or second decade.
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Signs
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A solitary slightly or moderately elevated pigmented or partially pigmented lesion of variable size, most frequently juxtalimbal; over half contain small cysts ( Figs 12.1C and D ).
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Naevi are mobile over the underlying sclera.
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The extent of pigmentation is variable; absence is relatively common ( Fig. 12.1E ).
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The plica, fornix and caruncle ( Fig. 12.1F ) are uncommon locations.
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Naevi may become inflamed, especially in children and adolescents, and this may be mistaken for malignant change.
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Signs of potential malignancy
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An unusual site such as the palpebral or forniceal conjunctiva.
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Prominent feeder vessels.
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Sudden growth or increase in pigmentation.
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Development after the second decade.
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Conjunctival papilloma
Conjunctival papillomata are strongly associated with human papillomavirus infection, especially types 6 and 11. Histopathologically they consist of a fibrovascular core covered by an irregular proliferation of non-keratinized stratified squamous epithelium containing goblet cells ( Fig. 12.2A ).
Clinical features
Lesions are sessile (wide base and flattish profile – Figs 12.2B and C ) or pedunculated (frond-like – Fig. 12.2D ), and are frequently located in the juxtalimbal area, fornix or the caruncle. They are usually solitary but may be multiple.
Large lesions may cause irritation, interfere with lid closure or encroach onto the cornea.
Treatment
Small lesions may resolve spontaneously. Large lesions are treated by excision, sometimes with cryotherapy to the base and the surrounding area. Options for recurrences include subconjunctival interferon alfa, carbon dioxide laser vaporization, topical mitomycin C and oral cimetidine.
Limbal dermoid
A limbal dermoid is a choristoma (a mass of histologically normal tissue in an abnormal location) consisting of a mass of collagenous tissue containing dermal elements; it is covered by stratified squamous epithelium ( Fig. 12.3A ). Presentation is in early childhood, with a smooth, yellowish, soft subconjunctival mass commonly located at the inferotemporal limbus, often with protruding hair ( Fig. 12.3B ). Lesions are occasionally very large and may virtually encircle the limbus ( Fig. 12.3C ). Treatment is indicated for cosmesis, chronic irritation, dellen formation and amblyopia from astigmatism or involvement of the visual axis. Small dermoids can undergo simple excision, but lamellar keratosclerectomy may be required for large lesions.
Systemic associations
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Goldenhar syndrome (oculoauriculovertebral spectrum – Fig. 12.3D ) is usually sporadic.
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Systemic features include hypoplasia of the malar, maxillary and mandibular regions, macrostomia and microtia, preauricular and facial skin tags, hemivertebrae (usually cervical), mental handicap, cardiac, renal and central nervous system (CNS) anomalies.
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Ocular features, apart from dermoids, include upper lid notching or coloboma, microphthalmos and disc coloboma.
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Treacher Collins syndrome (see Ch. 1 ).
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Linear naevus sebaceus of Jadassohn.
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Systemic features include warty or scaly cutaneous lesions, infantile spasms, CNS anomalies and developmental delay.
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Ocular features, apart from dermoids, include ptosis, cloudy cornea, lid colobomas, fundus colobomas and microphthalmos.
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Dermolipoma
A dermolipoma is similar in composition to a solid dermoid but also contains fatty tissue. Presentation tends to be in adult life as a soft yellowish subconjunctival mass near the outer canthus ( Fig. 12.4A ). The surface is usually keratinized, and in common with a dermoid, may exhibit hairs. Occasionally the lesion may extend into the orbit or anteriorly towards the limbus. Treatment is generally avoided due to the possibility of complications such as scarring, ptosis, dry eye and ocular motility problems. In selected cases, debulking the anterior portion may improve cosmesis with lower risk. It is critical to distinguish a dermolipoma from a prominent lacrimal gland lobe and from orbital fat prolapse ( Fig. 12.4B ); lymphoma can also present in a similar fashion.
Pyogenic granuloma
A pyogenic granuloma is a fibrovascular proliferative response to a conjunctival insult such as surgery or trauma, or in association with a chalazion or foreign body incarceration. Histology shows granulation tissue with both acute and chronic inflammatory cells and a proliferation of small blood vessels; the term pyogenic granuloma is a misnomer as the lesion is neither pyogenic nor granulomatous. Presentation is typically a few weeks after surgery for chalazion, strabismus or enucleation, with a rapidly growing dark pink fleshy conjunctival mass ( Fig. 12.5A ). Treatment with topical steroids is often successful; resistant cases require excision. The differential diagnosis includes suture granuloma, which can often be large and mistaken for a malignant lesion ( Fig. 12.5B ) and Tenon capsule granuloma or cyst.
Miscellaneous benign epibulbar tumours
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Epibulbar telangiectasia ( Fig. 12.6A ) may be associated with Sturge–Weber syndrome.
Fig. 12.6
Miscellaneous benign conjunctival tumours. (A) Epibulbar telangiectasia in Sturge–Weber syndrome; (B) reactive pseudoepitheliomatous hyperplasia; (C) melanocytoma
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Reactive pseudoepitheliomatous hyperplasia is a rapidly growing white juxtalimbal hyperkeratotic nodule ( Fig. 12.6B ) that develops secondary to irritation.
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Melanocytoma is a rare congenital lesion. It manifests as a slowly enlarging black lump ( Fig. 12.6C ) that cannot be moved freely over the globe.
Benign melanosis
Benign conjunctival epithelial melanosis (conjunctival hypermelanosis) is a normal variant, more common in darker-skinned individuals (over 90% of blacks, 5% of whites) due to the presence of excess melanin within basal layer conjunctival epithelial melanocytes. Melanocyte numbers are normal, that is, there is no melanocytic hyperplasia. It may have a protective effect against neoplasia. Benign melanosis appears during the first few years of life, and becomes static by early adulthood; both eyes are affected but involvement may be asymmetrical. Areas of flat, patchy, brownish pigmentation may be seen throughout the conjunctiva but are often concentrated at the limbus ( Fig. 12.7A ) and around perforating branches of vessels or nerves as they enter the sclera ( Fig. 12.7B ). The pigmented epithelium moves freely over the surface of the globe. A variant is seen in which small cysts are present.
Malignant and Premalignant Epibulbar Tumours
Primary acquired melanosis/conjunctival melanocytic intra-epithelial neoplasia
Introduction
Approximately 75% of conjunctival melanomas (see below) arise in areas of melanocytic hyperplasia. Recent trends in the description of pigmented conjunctival lesions have led to controversy relating to terminology. Some classifications have historically used the term primary acquired melanosis (PAM) to encompass both benign epithelial melanosis (see above) and melanocytosis/melanocytic hyperplasia (with and without atypia), whilst others have restricted its use to the latter category. To avoid this ambiguity, the term conjunctival melanocytic intra-epithelial neoplasia (C-MIN) may be preferred for lesions exhibiting proliferation of melanocytes, with PAM reserved for clinical description before a histological diagnosis has been established. The differential diagnosis includes conjunctival naevus, benign melanosis, congenital ocular melanocytosis (see below), secondary pigmentation in Addison disease and pigmented squamous cell carcinoma.
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PAM without cellular atypia or with mild atypia is a benign intraepithelial proliferation of epithelial melanocytes ( Fig. 12.8A ) with little or no risk of malignant transformation.
Fig. 12.8
Primary acquired melanosis (PAM). (A) Histology shows intraepithelial proliferation of conjunctival epithelial melanocytes; (B) small area of PAM; (C) more extensive PAM; (D) tarsal PAM associated with lentigo maligna of the eyelid
(Courtesy of J Harry and G Misson, from Clinical Ophthalmic Pathology , Butterworth-Heinemann 2001 – fig. A; C Barry – fig. C; D Selva – fig. D)
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PAM with severe atypia can be regarded as melanoma in situ that has a substantial chance of progression to invasive melanoma over several years. The risk is higher the greater the extent of the lesion, measured in clock hours. Severe atypia is present in only a small minority of PAM.
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C-MIN is graded from 0 to 10 according to degree of atypia and spread, 0 corresponding to an absence of any melanocyte proliferation or atypia (i.e. melanosis only) and 5 to conjunctival melanoma in situ .
Diagnosis
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Symptoms. A pigmented area is noticed on the surface of one or both (10%) eyes at a median age of 56 years, usually in a white individual.
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Signs
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Uni- or multifocal flat areas of irregular golden-brown to dark chocolate-coloured epithelial pigmentation, typically involving the limbus and interpalpebral region ( Figs 12.8B and C ). PAM sine pigmento has been reported.
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Because any part of the conjunctiva may be affected, it is important to evert the eyelids ( Fig. 12.8D ); C-MIN may also extend onto the cornea.
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Transformation to melanoma may be suggested by the appearance of nodular areas.
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Investigation. Careful documentation with drawing and/or photography of lesions undergoing observation is important. Immunohistochemical analysis of biopsied lesions is performed.
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Treatment
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Observation of small (less than one clock hour) lesions may be appropriate; some advocate excision biopsy of every lesion.
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Excision biopsy is generally preferred to incisional biopsy if possible (see under conjunctival melanoma below for surgical approach).
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Double freeze–thaw cryotherapy may be administered to the excision site, and/or following histological confirmation of C-MIN postoperative topical mitomycin C, e.g. four cycles of 0.04% four times daily for 7 days separated by 3-week intervals, with punctum plugs in situ to reduce the risk of punctal stenosis and increase drug–surface contact time.
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Amniotic membrane grafting may be necessary for large excision sites.
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Larger lesions: mapping incisional biopsies can be accompanied by cryotherapy to all pigmented areas or topical mitomycin C as above.
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Long-term follow-up is mandatory in all cases.
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Corneal involvement: alcohol-mediated epitheliectomy followed by topical mitomycin C.
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Conjunctival melanoma
Conjunctival melanoma is rare, accounting for about 2% of all ocular malignancies. Around 75% arise from an area of PAM, about 25% from a pre-existing junctional or compound naevus and rarely de novo . Presentation is often in the sixth decade, though patients with the rare dysplastic naevus syndrome develop multiple melanomas at a considerably younger age. The differential diagnosis includes naevus, ciliary body melanoma with extraocular extension, melanocytoma and pigmented conjunctival squamous carcinoma. The overall mortality is up to 19% at 5 years and 30% at 10 years. Metastasis occurs in 20–30%; the main sites are regional lymph nodes, lung, brain and liver. Factors associated with a worse prognosis include caruncular, forniceal or lid margin location and tumour thickness of 2 mm or more.
Diagnosis
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Appearance. A black or grey vascularized nodule that may be fixed to the episclera. The limbus is a common site, but a melanoma may arise anywhere in the conjunctiva ( Fig. 12.9A ). Association with PAM/C-MIN is very common ( Fig. 12.9B ).
Fig. 12.9
Conjunctival melanoma. (A) Conjunctival melanoma extending into the eyelid; (B) multifocal melanoma arising from PAM; (C) amelanotic melanoma; (D) histology showing melanoma cells within the epithelium and subepithelial stroma
(Courtesy of C Barry – fig. A; J Harry – fig. D)
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Amelanotic tumours may give rise to diagnostic difficulty ( Fig. 12.9C ).
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B-scan ultrasonography may be helpful in characterization of the lesion.
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Systemic screening consists of regular general examination, liver function testing and ultrasound, chest X-ray and possibly whole body positron emission tomography/computed tomography (PET/CT) imaging where available.
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Histology shows melanomatous cellular atypia with invasion of the subepithelial stroma ( Fig. 12.9D ).
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Sentinel lymph node biopsy may be helpful in staging, though its place has not yet been fully defined.
Treatment
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Circumscribed lesions are treated by excision with a wide margin. As tumour seeding can occur during excision, contact with the tumour itself should be avoided and fresh instruments used to close the conjunctival defect.
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Adjunctive radiotherapy is routinely administered by some authorities, even if histology suggests that excision is complete; cryotherapy to the bed and surrounding tissue is an alternative. Proton beam radiotherapy can be applied if the caruncle or fornix is involved.
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Diffuse melanoma associated with extensive PAM/C-MIN is treated by excision of localized nodules with mitomycin C or cryotherapy to the diffuse component.
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Orbital recurrences are treated by local resection and radiotherapy. Exenteration may not improve survival and is therefore reserved for patients with extensive and aggressive disease when the eye cannot be preserved.
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The drug vemurafenib improves survival in patients with metastatic disease when the BRAF V600E mutation is present (50% of primary and metastatic conjunctival melanomas).
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Multifocal disease, non-limbal tumour location, tumour margin involvement and lack of adjunctive treatment are associated with a greater likelihood of recurrence.
Ocular surface squamous neoplasia
Introduction
Ocular surface squamous neoplasia (OSSN) describes a spectrum of benign, pre-malignant and malignant slowly progressive epithelial lesions of the conjunctiva and cornea. Older adults are usually affected unless a predisposing systemic condition is present. Risk factors include ultraviolet light exposure, a pale complexion, ciclosporin, smoking, petroleum product exposure, acquired immunodeficiency syndrome (AIDS) and xeroderma pigmentosum. Human papilloma virus infection (especially type 16) has been implicated in some cases. Metastatic disease is extremely rare.
Diagnosis
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Symptoms. A visible mass in one eye, sometimes accompanied by conjunctivitis-type symptoms.
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Signs are variable and clinical correlation with histological severity is unreliable. Most tend to develop within the interpalpebral fissure, particularly at the limbus, although any part of the conjunctiva or cornea may be involved. The lesion may appear fleshy, gelatinous, leukoplakic or papillomatous, superficial or feeder vessels may be prominent or the appearance may be avascular ( Figs 12.10A–C ). Intraocular extension is uncommon.
Fig. 12.10
Ocular surface squamous neoplasia. (A) Relatively small lesion; (B) larger gelatinous lesion stained with rose Bengal; (C) leukoplakic lesion; (D) histology of squamous cell carcinoma shows downward proliferation of irregular dysplastic epithelium with infiltration of subepithelial tissue
(Courtesy of B Damato – fig. C; J Harry – fig. D)
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Investigations include ultrasonic biomicroscopy (UBM) or anterior segment optical coherence tomography (OCT) to estimate the depth of invasion, exfoliative cytology and impression cytology.
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Histology shows the following spectrum; the first two are sometimes termed conjunctival–corneal intraepithelial neoplasia (CCIN):
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Conjunctival epithelial dysplasia. Dysplastic cells are confined to the basal epithelial layers.
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Carcinoma in situ . Dysplastic cells involve the full thickness of the epithelium.
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Squamous cell carcinoma. Invasion of the underlying stroma ( Fig. 12.10D ).
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Treatment
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Excision with 2–4 mm margins and assessment for completeness of clearance, often with intraoperative frozen section, has been the conventional standard approach. Complete histological excision is associated with recurrence of 5–33%. Adjunctive measures reduce recurrence and include cryotherapy, brachytherapy or topical chemotherapy.
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Topical chemotherapy. Traditionally used as adjunctive treatment, this may also be employed as a primary modality to avoid the scarring and stem cell damage associated with extensive excision, to reduce tumour size prior to excision, or to treat recurrence. Agents include mitomycin C, 5-fluorouracil and interferon alfa-2b eye drop regimens; the latter two tend to be better tolerated.
Lymphoproliferative lesions
Introduction
The most common conjunctival lymphoproliferative lesion is reactive lymphoid hyperplasia, a proliferation of both B and T cells with germinal follicle formation. Conjunctival lymphoma may arise de novo , by extension from orbital lymphoma or associated with systemic lymphoma at diagnosis (up to 30%). Most conjunctival lymphomas are of B cell origin, arising from mucosa-associated lymphoid tissue (MALT) and tending to be indolent.
Diagnosis
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Symptoms. Painless swelling, redness or irritation; this is often bilateral, when systemic disease is more likely. Other possible symptoms include ptosis and diplopia.
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Signs. A slowly growing salmon-pink or flesh-coloured mobile infiltrate is seen on the epibulbar surface or in the fornices ( Figs 12.11A and B ). Rarely, a diffuse lesion may mimic chronic conjunctivitis.
Fig. 12.11
Conjunctival lymphoproliferative lesions. (A) Epibulbar lymphoma; (B) large conjunctival lymphoma
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Biopsy is taken to confirm diagnosis; the uninvolved eye should also be biopsied (inferior fornix).
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Investigation for systemic involvement.
Treatment
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Systemic disease is treated as indicated, when local conjunctival measures may not be required.
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External beam radiotherapy .
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Other options include chemotherapy, excision of small lesions with adjuvant treatment, cryotherapy and intralesional injections of interferon alfa-2b or rituximab.
Kaposi sarcoma
Kaposi sarcoma is a slowly growing tumour that is typically found in patients with AIDS, but occasionally in the elderly and when there is long-term immunosuppression. A vascular bright red or purplish plaque or nodule is seen ( Fig. 12.12 ), sometimes resembling (or associated with) conjunctival haemorrhage. Histology reveals a proliferation of spindle-shaped cells, vascular channels and inflammatory cells. If treatment is necessary, systemic AIDS therapy should be optimized, with local radiotherapy, excision and local or systemic chemotherapy as additional options.
Iris Tumours
Iris naevus
Iris naevi consist of a proliferation of melanocytes in the superficial iris stroma, and appear as a circumscribed solitary flat or variably elevated pigmented lesion ( Figs 12.13A–D ). The normal iris architecture is disrupted. A diffuse naevus characteristically occurs in congenital ocular melanocytosis and in iris naevus (Cogan–Reese) syndrome (see Ch. 10 ). The malignant transformation rate is up to 8% over 15 years; risk factors include young age (under 40), inferior location, bleeding from the lesion, diffuse iris involvement, feathery margins and ectropion uveae. Observation should be life-long and involve documentation by slit lamp examination and photography. Review should also include serial fundus examination, as iris naevus is a marker for all forms of uveal melanoma.
Iris freckle (ephelis)
Iris freckles (ephelides) are superficial lesions that are smaller than naevi, with no elevation or distortion ( Fig. 12.14A and see Fig. 12.13A ), and show increased melanocyte pigmentation but with a normal number of cells.
Brushfield spots
These are small whitish peripheral iris speckles arranged in a concentric ring ( Fig. 12.14B ), occurring particularly in Down syndrome though also as a normal finding in lighter irides. They consist of a focal mildly hyperplastic focus surrounded by a ring of hypoplasia and have no malignant potential (see also Ch. 9 ).
Lisch nodules
These are small well-defined nodules ( Figs 12.14C and D ) found in both eyes of virtually all patients with neurofibromatosis type 1 (see Ch. 19 ).
Iris melanoma
Introduction
About 8% of uveal melanomas arise in the iris. The prognosis is comparatively good – only about 5% of patients develop metastasis within 10 years of treatment. Conditions associated with or predisposing to uveal melanomas include fair skin and lighter iris colour, numerous and/or atypical (dysplastic) cutaneous naevi, iris or choroidal naevi, congenital ocular and oculodermal melanocytosis (naevus of Ota) and uveal melanocytoma. Chronic sunlight exposure and arc welding are environmental risk factors. Presentation is typically in middle age, a decade earlier than ciliary body and choroidal melanoma.
Diagnosis
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Symptoms. Enlargement of a pre-existing naevus is typical, noticed either by the patient or at a routine eye examination. Signs indicative of malignant transformation include growth ( Fig. 12.15 ) and the development of prominent blood vessels (see Fig. 12.13C ).
Fig. 12.15
Iris melanoma enlarging over several years
(Courtesy of C Barry)
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Signs
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A pigmented ( Fig. 12.16A ) or non-pigmented ( Fig. 12.16B ) nodule at least 3 mm in diameter and 1 mm thick, typically located in the inferior half of the iris and often associated with surface blood vessels.
Fig. 12.16
Iris melanoma. (A) Typical iris melanoma; (B) amelanotic tumour; (C) angle invasion and extrascleral extension; (D) histology shows infiltration of the entire thickness of the stroma
(Courtesy of C Barry – figs A and C; J Harry and G Misson, from Clinical Ophthalmic Pathology , Butterworth-Heinemann 2001 – fig. D)
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Pupillary distortion, ectropion uveae and occasionally localized cataract may be seen, although these can also occur with naevi.
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Growth is usually slow, with extension across the iris surface.
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The angle and anterior ciliary body may be infiltrated; extrascleral extension is rare ( Fig. 12.16C ).
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Complications include hyphaema, cataract and glaucoma.
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Histology in the majority shows diffusely infiltrating spindle cells (see below) of low-grade malignancy ( Fig. 12.16D ). A minority contain an epithelioid cell component and can be more aggressive.
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Ultrasound biomicroscopy is used to rule out ciliary body involvement.
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Fine-needle aspiration biopsy may be employed prior to major surgical intervention.
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Systemic investigation should be carried out.
Treatment
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Sector iridectomy for small tumours, and iridocyclectomy for tumours invading the angle.
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Radiotherapy with a radioactive plaque (brachytherapy) or external irradiation with a proton beam.
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Enucleation may be required for diffusely growing tumours, if radiotherapy is not possible.
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Monitoring for recurrence and metastasis.
Metastatic tumours
Metastasis to the iris ( Figs 12.17A and B ) is rare and is characterized by one or more fast-growing white, pink or yellow masses that may be associated with anterior uveitis and occasionally hyphaema. Breast and lung cancer and melanoma of the skin are among the most common types.
Miscellaneous iris tumours
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Juvenile xanthogranuloma is a rare idiopathic granulomatous disease of early childhood that involves the skin, muscle, stomach, salivary glands and other organs. Iris involvement is characterized by a localized or diffuse yellow lesion ( Fig. 12.18A ) that may be associated with spontaneous hyphaema or, less commonly, anterior uveitis and glaucoma. Treatment is with topical steroids.
Fig. 12.18
(A) Juvenile iris xanthogranuloma; (B) leiomyoma; (C) melanocytoma; (D) racemose haemangioma; (E) supplying and draining vessels for lesion in (D)
(Courtesy of BJ Zitelli and HW Davis, from Atlas of Pediatric Physical Diagnosis , Mosby 2002 – fig. A; B Damato – fig. B)
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Leiomyoma is an extremely rare benign tumour arising from smooth muscle. The appearance is similar to that of an amelanotic melanoma ( Fig. 12.18B ).
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Melanocytoma is a darkly pigmented nodular mass with a mossy, granular surface, most frequently occupying the peripheral iris ( Fig. 12.18C ). It may undergo spontaneous necrosis resulting in seeding of the iris stroma and chamber angle, with elevation of intraocular pressure.
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Vascular tumours of various types have been described, the most common being racemose haemangioma (arteriovenous communication), typically seen as a large ectatic vessel and/or bunch of grapes ( Figs 12.18D and E ).
Iris Cysts
Iris cysts are rare lesions. Anterior segment OCT and ultrasound biomicroscopy are especially useful to differentiate some lesions from ciliary body tumours.
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Primary epithelial cysts
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Cysts arise from the iris or iridociliary pigment epithelium.
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Three-quarters are in the peripheral iris, where they appear as a smooth dome-shaped bulging ( Fig. 12.19A ) best seen on gonioscopy ( Fig. 12.19B ). Mid-zone lesions again appear as a bulge in the iris – the wall may be manifest on pupillary dilatation. At the pupillary margin (least common), cysts appear darkly pigmented and often elongated.
Fig. 12.19
Primary iris cysts. (A) Subtle dome-shaped elevation of the peripheral iris due to an epithelial cyst; (B) gonioscopy of lesion in (A) ; (C) dislodged epithelial cyst in the angle; (D) very large stromal cyst
(Courtesy of Centre for Eye Health, Sydney – fig. A; J McAllister – fig. D)
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They may rarely dislodge to float freely in the anterior chamber or vitreous ( Fig. 12.19C ).
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The vast majority are asymptomatic and innocuous. Rarely, large cysts may obstruct vision and require collapse with photocoagulation.
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Primary stromal cysts may be congenital (more aggressive) or acquired.
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Solitary unilateral structure with a smooth translucent anterior wall lying on or within the iris ( Fig. 12.19D ). Contained debris may be visible.
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May remain stable for many years before enlarging; can sometimes rupture.
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Most congenital cysts require treatment by aspiration or surgical excision. Ethanol-induced sclerosis may avoid the need for excision.
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Secondary cysts
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Traumatic cysts ( Fig. 12.20A ) occur following deposition of epithelial cells from the conjunctiva or cornea onto the iris after penetrating or surgical trauma. They frequently enlarge, leading to corneal oedema, anterior uveitis and glaucoma.
Fig. 12.20
Secondary iris cysts. (A) Traumatic cyst; (B) pupillary border cysts due to miotic therapy
(Courtesy of S Chen – fig. A; R Bates – fig. B)
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Extended use of long-acting miotics may be associated with usually bilateral small, multiple cysts located along the pupillary border ( Fig. 12.20B ). Their development can be prevented by the concomitant use of topical phenylephrine 2.5%.
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Parasitic cysts are extremely rare.
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Ciliary Body Tumours
Ciliary body melanoma
Introduction
Ciliary body melanomas comprise around 12% of all uveal melanomas. Risk factors are as for iris melanoma. Presentation is usually in the sixth decade with visual symptoms, although occasionally discovery is incidental; diagnosis may be delayed as the lesion is easily missed. Distinction is principally from an iridociliary cyst though uveal effusion syndrome may cause diagnostic difficulty that can be resolved by imaging. Other ciliary body tumours are extremely rare and include melanocytoma, medulloepithelioma, metastases, adenocarcinoma, adenoma, neurolemmoma and leiomyoma.
Diagnosis
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Signs
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A large tumour may be visualized with pupillary dilatation ( Fig. 12.21A ).
Fig. 12.21
Ciliary body melanoma. (A) Tumour seen on fundoscopy; (B) ‘sentinel’ vessels in the same quadrant as the tumour; (C) extraocular extension; (D) pressure on the lens
(Courtesy of B Damato – fig. B; R Curtis – fig. D)
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Overlying prominent episcleral (sentinel) vessels ( Fig. 12.21B ).
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Erosion through the iris root may mimic iris melanoma, extraocular extension through scleral vessels a conjunctival melanoma ( Fig. 12.21C ).
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Displacement of the lens ( Fig. 12.21D ) may cause astigmatism, subluxation or cataract.
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Investigations
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Three-mirror contact lens examination and binocular indirect ophthalmoscopy.
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Gonioscopy to detect angle invasion.
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Ultrasonic biomicroscopy.
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Biopsy involving excisional, incisional or fine-needle aspiration techniques may be helpful in selected cases. Genetic profiling may help to determine the likelihood of metastasis (see choroidal melanoma).
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Investigation for systemic involvement, particularly hepatic.
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Treatment
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Iridocyclectomy or sclerouvectomy for small or medium-sized tumours involving no more than one-third of the angle. Complications include retinal detachment, vitreous haemorrhage, cataract, lens subluxation, hypotony and incomplete resection.
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Radiotherapy by brachytherapy or proton beam irradiation.
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Enucleation may be necessary for large tumours.
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Systemic treatment is indicated when metastatic disease is evident.
Medulloepithelioma
Medulloepithelioma (previously known as diktyoma) is a rare embryonal neoplasm that arises from the inner layer of the optic cup and can be benign or malignant. Presentation is usually in the first decade with visual loss, pain, photophobia, leukocoria, or proptosis in advanced cases. A white, pink, yellow or brown ciliary body, retrolental or anterior chamber mass is seen ( Figs 12.22A and B ). Enucleation may be required.
Tumours of the Choroid
Choroidal naevus
Choroidal naevi are present in 5–10% of Caucasians but are rare in darker-skinned races. Growth occurs mainly during the pre-pubertal years and is extremely rare in adulthood. For this reason clinically detectable growth should raise a suspicion of malignancy. The lifetime risk of malignant transformation is up to 1% from tertiary centre data. Histologically, the tumour is composed of a proliferation of spindle cell melanocytes within the choroid ( Fig. 12.23A ). It is vital to identify features suggesting a greater likelihood of malignancy; as with cutaneous melanoma, early treatment is associated with a substantially lower risk of metastasis. An extended period without any change provides no guarantee that progression will not occur in the future, as sudden enlargement of naevi has been documented following many years of stability.
