Ocular tumors are a collection of cells that grow and multiply abnormally and form masses. These can appear on the eyelids, in the eye, and in the orbit. The tumors in the eye are usually secondary tumors, that is, metastatic from another part of the body (lung, breast, prostate, etc). Two types of primary tumors arise within the eye itself: retinoblastoma in children and melanoma in adults. Ocular tumors can be epibulbar or intraocular. All these tumors may be benign or malignant (Flowchart 18.1).
Epibulbar tumors clinically manifest with a very wide spectrum and include several forms of epithelial, stromal, caruncular, and secondary tumors. These may be classified as given in Flowchart 18.2.
These are not true tumors but choristomas (a mass of histologically normal tissue in an abnormal location) and include dermoids and dermolipomas.
Dermoid (OP2.1, 2.2)
It is a congenital tumor and consists of epidermoid epithelium containing sebaceous glands and hairs. It is located at the limbus (Fig. 18.1). It presents as yellowish, soft conjunctival mass in early childhood. Treatment includes simple excision if the tumor is small in size, but lamellar keratosclerotomy may be required if the tumor is large in size.
It is a congenital tumor and consists of fibrous tissue and fat (fibro fatty tumors). It is commonly located at the outer canthus (Fig. 18.2). It presents as soft, yellowish subconjunctival mass in adult life. Treatment is generally avoided due to the possibility of complications.
Congenital epibulbar choristomas may have systemic association known as Goldenhar syndrome (Ocular auriculo vertebral anomalies) which is characterized by the following:
•Ocular features: Apart from dermoids, upper lid coloboma, microphthalmos, and disc anomalies have been reported.
•Systemic features: These include preauricular skin tags, vertebral anomalies, and hemifacial hypoplasia.
Benign tumors do not invade nearby tissue or spread to other parts of the body but they can be serious if they press on vital structures such as blood vessels or nerves. Therefore, at times, they require treatment, and at other times they do not.
Conjunctival Naevus (Conjunctival Mole)
It is congenital and tends to grow at puberty. It presents as elevated pigmented nodule in the first or second decade. It is located at the limbus or near plica semilunaris (Fig. 18.3). Naevi are mobile over underling sclera. Vast majority of naevi do not undergo malignant transformation. It is treated by simple excision which is performed for cosmetic purposes or on suspicion of malignancy.
It is sessile or pedunculated and strongly associated with human papilloma virus infection. It is located at the limbus, near canthus or in the fornices (Fig. 18.4). Treatment includes excision performed with cryotherapy at the base and surrounding area, but recurrence rate is high.
It is a fibrovascular proliferation in response to conjunctival surgery, trauma, or foreign body incarceration, and consists of granulation tissue with inflammatory cells and blood vessels. It is treated by topical steroids but excision is carried out in resistant cases.
Conjunctival Epithelial Melanosis
It occurs due to the presence of excess melanin epithelial melanocytes in conjunctival basal layer. So, it is more common in darker-skinned individuals. There is no melanocytic hyperplasia. It is bilateral and appears during the first few years of life. It presents as patchy flat brownish pigmentation of conjunctiva and requires no treatment as it has no malignant potential.
Bowen Intra Epithelial Epithelioma (Carcinoma in Situ)
It is a premalignant tumor of conjunctival epithelium. It has a chance of progression to invasive melanoma. It usually begins near the limbus. As it is superficial to basement membrane, conjunctiva is freely movable over underlying episcleral tissue. It is treated by surgical excision with adjunctive cryotherapy or topical Mitomycin C or 5-FU to avoid recurrence.
Squamous Cell Carcinoma (Epithelioma)
It occurs at the epithelial transition zone. Therefore, it chiefly occurs at the limbus and the lid margin. It appears fleshy, and gelatinous with feeder vessels. Intraocular extension is uncommon (Fig. 18.5). It is treated by excision with cryotherapy of base. If recurrence takes place, enucleation or even exenteration may be necessary along with radiotherapy.
It is rare, usually pigmented, and often occurs in the 6th decade. It occurs typically at the limbus and spreads over the surface of the globe (Fig. 18.6). It rarely penetrates it. The main sites of metastasis are lymph nodes, liver, lung, and brain. It may require excision of globe or exenteration of orbit.
Intraocular tumors include tumors of uveal tract and retina (Flowchart 18.3).
■Benign Tumors of Uvea
Uveal naevus is a benign tumor arising from the melanocytic cells. It occurs most commonly in the choroid but also occurs in the iris or ciliary body. Most naevi are likely to be congenital in nature but detectable clinically until after childhood. Most uveal naevi are asymptomatic; however, macular choroidal naevi can cause visual loss.
Naevus of Iris
It is a localized flat or elevated stromal lesion and can cause pupillary distortion, ectropion iridis, or both (Fig. 18.7). It is rarely associated with abnormal iris vasculature. Iris naevus must be differentiated from the multiple, small, yellow or brown, melanocytic iris lesions elevated above the iris surface (Lisch nodules). Lisch nodules appear to be nodular aggregates of dendritic melanocytes and not true naevi. Lisch nodules are pathognomonic of neurofibromatosis, that is, these are found on the iris of patient with neurofibromatosis.
It characteristically arises from the nonpigmented epithelium of ciliary body. Its characteristic features are:
•It is amelanotic tumor arising mainly in the ciliary body.
•The average age of affected individual is approximately 5 years. So, it affects infants and young children preferentially.
•It typically appears as brown to white lesions of extreme peripheral fundus and detectable only by indirect ophthalmoscope with scleral depression because of its peripheral location.
•Its common complication is the development of neovascular glaucoma.
Medulloepithelioma can be detected by the following investigations:
It appears as a small gray to brown choroidal tumor. Choroidal naevi are usually small (less than 2DD [disc diameter]) with indistinct margins. A lesion > 5DD must be considered malignant. They are usually associated with characteristic surface alterations such as drusen and pigment clumping in retinal pigment epithelium (RPE). It is asymptomatic but may cause blurred or distorted vision due to accumulation of serous subretinal fluid. It may result in localized serous detachment of RPE or neurosensory retina.
Choroidal naevus can be detected by the following investigations:
•Ultrasonography (to measure the size and extent of choroidal naevus).
•Fluorescein angiography (FA) and indocyanine green (ICG) angiography to assess the presence of prominent blood vessels within the tumor. Choroidal naevus is defined better by ICG angiography than by FA.
Most benign choroidal naevi do not have blood vessels within the tumor, but choroidal melanomas do have blood vessels within the tumor.
It is a benign vascular tumor of choroid and occurs in two forms: circumscribed and diffuse.
Circumscribed choroidal hemangioma: These are reddish–orange, round to oval tumors and located in the posterior half of fundus. Such tumors almost never extend anterior to equator and are located within 2DD from the optic disc, foveola, or both. Circumscribed choroidal hemangioma results in degenerative changes in overlying RPE. Accumulation of serous subretinal fluid or degenerative changes in macular retina produce visual symptoms (blurred vision and metamorphopsia).
Diffuse choroidal hemangioma: It is usually a part of the Sturge–Weber syndrome. The choroid is thickened diffusely by the hemangiomatous vascular lesion, and the fundus on the affected side has a more saturated red appearance than the fundus on the uninvolved side. It is referred as “tomato ketchup fundus.”
Choroidal hemangioma may cause elevated IOP (secondary glaucoma) and exudative retinal detachment.
Choroidal hemangioma can be detected by the following investigations:
•Indocyanine green angiography
Laser photocoagulation is the mainstay of treatment.
It is a benign, acquired bony tumor of the choroid. It is orange to pale yellow, juxtapapillary choroidal tumor. It is usually unilateral (in 70–80% cases) and more common in females. The margins of lesions are typically irregular in contour. If the lesions involve the macula, visual acuity is impaired. In some cases, a choroidal neovascular membrane arises and produces exudative retinal detachment.
Choroidal osteoma can be detected by the following investigations:
Due to the lack of pigment in the tumor and atrophy of the overlying RPE, conventional laser photocoagulation has limited effect. Photodynamic therapy is conducted for secondary choroidal neovascularization if the macula is not involved.
■Malignant Tumors of Uvea (Uveal Melanoma)
It is the primary acquired malignant neoplasm of uveal melanocytes and can arise from any portion of the uveal tract. Therefore, it can be:
•Iris melanoma (melanoma confined to iris).
•Ciliary body melanoma (melanoma confined to ciliary body).
•Choroidal melanoma (melanoma confined to choroid). Choroidal involvement is the most common.
The average age at detection of choroidal or ciliary body melanomas is approximately 55 to 60 years, and the average age at detection of iris melanomas is 10 to 20 years previously. Uveal malignant melanoma is rare in persons younger than 30 years.
Metastatic spread is via the hematogenous route. The most common metastatic site is liver.
All uveal melanomas are composed of anaplastic melanocytes having greater nuclear-to- cytoplasmic ratio. Tumor cells having less pronounced anaplasia are termed spindle melanoma cells. Tumor cells which exhibit more pronounced anaplasia are called epitheloid melanoma cells. Uveal melanomas are generally classified as:
•Spindle cell melanoma.
•Mixed cell melanoma.
•Epitheloid cell melanoma.
Spindle cell melanoma has the most favorable survival prognosis. Epitheloid cell melanoma has least favorable survival prognosis. Mixed cell melanoma has intermediate survival prognosis.
It presents as a solitary pigmented or nonpigmented dark brown nodule. Prominent intralesional blood vessels frequently develop within iris melanomas which are responsible for spontaneous hyphema (Fig. 18.8). Other features include: