TUMOURS OF THE CONJUNCTIVA

Classification
Non-pigmented tumours
I. Congenital: dermoid and lipodermoid (choristomas).
II. Benign: simple granuloma, papilloma, adenoma, fibroma and angiomas.
III. Premalignant: intraepithelial epithelioma (Bowen's disease).
IV. Malignant: epithelioma or squamous cell carcinoma, basal cell carcinoma.

Pigmented tumours (discussed in upcoming post)
I. Benign: naevi or congenital moles.
II. Precancerous melanosis: superficial spreading melanoma and lentigo maligna (Hutchinson's freckle).
III. Malignant: primary
melanoma (malignant melanoma).

A. Non-pigmented Tumours
I. Congenital tumours
1. Dermoids. These are common congenital tumours which usually occur at the limbus. They appear as solid white masses, firmly fixed to the cornea (Fig.
1). Dermoid consists of collagenous connective tissue, sebaceous glands and hair, lined by epidermoid epithelium. Treatment is simple excision.

Fig. 1. Limbal dermoid.

2. Lipodermoid (Fig. 2). It is a congenital tumour, usually found at the limbus or outer canthus. It appears as soft, yellowish white, movable subconjunctival mass. It consists of fatty tissue and the surrounding dermis-like connective tissue, hence the name lipodermoid. Sometimes the epibulbar dermoids or lipodermoids may be associated with accessory auricles and other congenital defects (Goldenhar's syndrome).

Fig. 2. Lipodermoid.

II. Benign tumours
1. Simple granuloma. It consists of an extensive polypoid, cauliflower-like growth of granulation tissue. Simple granulomas are common following squint surgery, as foreign body granuloma and following inadequately scraped chalazion.
Treatment consists of complete surgical removal.

2. Papilloma. It is a benign polypoid tumour usually occurring at inner canthus, fornices or limbus. It may resemble the cocks comb type of conjunctival tubercular lesion. It has a tendency to undergo malignant change and hence needs complete excision.

3. Fibroma. It is a rare soft or hard polypoid growth usually occurring in lower fornix.

  III. Pre-malignant tumours
Bowen's intraepithelial epithelioma (carcinoma insitu). It is a rare, precancerous condition, usually occurring at the limbus as a flat, reddish grey,
vascularised plaque. Histologically, it is confined within the epithelium. It should be treated by complete local excision.

IV. Malignant tumours
1. Squamous cell carcinoma (epithelioma) (Fig. 3). It usually occurs at the transitional zones i.e. at limbus and the lid margin. The tumour invades the stroma deeply and may be fixed to underlying tissues. Histologically, it is similar to squamous cell carcinomas occurring elsewhere .

Treatment. Early cases may be treated by complete local excision combined with extensive diathermy cautery of the area. However, in advanced and recurrent cases radical excision including enucleation or even exenteration may be needed along with postoperative radiotherapy.

Fig. 3. Squamous cell carcinoma at the limbus.

2. Basal cell carcinoma. It may invade the conjunctiva from the lids or may arise pari-passu from the plica semilunaris or caruncle. Though it responds
very favourably to radiotherapy, the complete surgical excision, if possible, should be preferred to avoid complications of radio- therapy.