Benign tumors of the conjunctiva and cornea

Tumors of the conjunctiva and cornea are considered together, since the corneal epithelium is topographically a continuation of the conjunctival epithelium. The rich connective tissue base of the conjunctiva predisposes to the occurrence of a wide range of tumors.

Benign tumors (dermoids, dermolipomas, pigmented tumors) predominate in the conjunctiva and cornea, and in childhood they account for more than 99% of all tumors in this location.

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Dermoid of the conjunctiva

Conjunctival dermoid is a developmental defect (choristoma); it accounts for about 22% of all benign conjunctival tumors in children. The tumor is detected in the first months of life. It is often combined with eyelid development defects and can be bilateral. Microscopic examination of the tumor reveals elements of sweat glands, fat lobules, and hair. Dermoid is a whitish-yellow formation, often located near the outer or lower-outer limbus. With such localization, the tumor spreads to the cornea early and can grow to its deep layers. Dilated vessels approach the neoplasm. The surface of the dermoid on the cornea is smooth, shiny, and white. Dermolipoma is a dermoid with a high content of fatty tissue, often localized in the area of the conjunctival fornices. Treatment of conjunctival dermoid is surgical.

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Conjunctival papilloma

Conjunctival papilloma most often develops in the first two decades of life and can be represented by two types. The first type of tumor is observed in children; it manifests itself as multiple nodules, most often localized on the lower fornix of the conjunctiva. Individual nodules can be observed in the conjunctiva of the eyeball or on the semilunar fold. The nodules are translucent with a smooth surface, consist of individual lobules penetrated by their own vessels, which gives them a reddish-pink color. The soft consistency and thin base in the form of a stalk makes the nodules mobile and easily injured: their surface bleeds even with a light touch of a glass rod. In older patients, keratinizing papilloma (type two) is usually localized near the limbus in the form of a single immobile formation of a grayish-white color. Its surface is rough, the lobules are poorly distinguishable. With such localization, the papilloma spreads to the cornea, where it looks like a translucent formation with a grayish tint. The first type of papilloma is microscopically represented by non-keratinizing papillary growths, in the center of which there are vascular loops. Such papillomas can spontaneously regress. Given the multifocal nature of the lesion, their surgical treatment is often ineffective; laser evaporation or applications of 0.04% mitomycin C solution to the affected area are indicated. Keratinizing papilloma (type two) is characterized by papillary hyperplasia of the epithelium with pronounced para- and hyperkeratosis. Such papilloma is subject to laser excision, since cases of its malignancy have been described. With complete removal of the tumor, the prognosis is good.

Bowen's epithelioma

Bowen's epithelioma is usually diagnosed in the fifth decade of life and later, more often in men. Usually the process is unilateral, monofocal. Etiological factors include ultraviolet radiation, prolonged contact with petroleum products, the presence of human papillomatosis virus. The tumor is a flat or slightly protruding plaque above the surface of the conjunctiva with clear boundaries of a gray color, with pronounced vascularization it can have a reddish tint. Bowen's epithelioma occurs in the epithelium, can penetrate into the deep layers of the conjunctiva, but the basement membrane always remains intact. Spreading to the cornea, the tumor does not grow through Bowman's membrane (anterior border plate). Treatment is surgical or combined, including treatment of the tumor with a 0.04% solution of mitomycin C 2-3 days before surgery, excision of the tumor and treatment of the surgical wound with a solution of mitomycin C on the operating table and in the following 2-3 days. Short-range radiotherapy is effective.

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Vascular tumors of the conjunctiva

Vascular tumors of the conjunctiva are represented by capillary hemangioma and lymphangioma; they belong to the group of hamartomas, are observed from birth or appear in the first months of life. Capillary hemangioma is most often localized in the inner corner of the eye slit, consists of sharply tortuous cyanotic vessels of small caliber that infiltrate the semilunar fold and the conjunctiva of the eyeball. Spreading to the fornices, the vessels can penetrate into the orbit. Spontaneous hemorrhages are possible. Treatment consists of dosed immersion electrocoagulation. At an early stage, laser coagulation is effective.

Conjunctival lymphangioma

Conjunctival lymphangioma is much less common than hemangiomas and is represented by widened thin-walled vascular canals of irregular shape, the inner surface of which is lined with endothelium. These canals contain serous fluid with an admixture of erythrocytes. The tumor is localized in the conjunctiva of the eyeball or its fornices. The semilunar fold and lacrimal caruncle are involved in the process. The tumor looks like a translucent yellowish thickening of the conjunctiva, consists of small lobules filled with transparent fluid, sometimes with an admixture of blood. Small hemorrhages are often visible on the surface of the lymphangioma. In the lobules and between them there are vessels filled with blood. The tumor infiltrates the soft tissues of the orbit. Small, uncommon lymphangiomas can be cured with a CO ₂ laser. For more widespread tumors, brachytherapy using a strontium applicator with the cornea removed from the irradiation zone may be recommended.

Nevi of the conjunctiva

Conjunctival nevus is a pigmented tumor of the conjunctiva, accounting for 21-23% of its benign neoplasms. It is first detected in childhood, less often in the second or third decade of life. According to the clinical course, nevi are divided into stationary and progressive, blue nevus and primary acquired melanosis.

Stationary conjunctival nevus is detected in small children. The favorite localization is the conjunctiva of the eyeball in the area of the eye slit, never occurs in the mucous membrane of the eyelids. The color of the nevus ranges from light yellow or pink to light brown with a well-developed vascular network. Usually the tumor is located near the limbus. Up to 1/3 of stationary nevi are non-pigmented. During puberty, the color of the nevus may change. The surface of the tumor is smooth or slightly rough due to the formation of small light cysts in it, the boundaries are clear. When localized in the conjunctiva of the eyeball, nevi easily move over the sclera, near the limbus they are immobile. Nevi localized in the area of the semilunar fold and lacrimal caruncle are usually found in adults. They are often more intensely pigmented (color from light to intense brown). There are frequent cases of focal pigmentation, especially nevi located in the area of the lacrimal caruncle. The semilunar fold is thickened with a nevus, and in the area of the lacrimal caruncle the tumor slightly protrudes. Its borders are clear.

Progressive nevus is characterized by an increase in size and a change in color. The surface of the nevus looks mottled: along with non-pigmented or weakly pigmented areas, zones of intense pigmentation appear, the tumor borders become less clear due to pigment dispersion. Pigment accumulation can be observed outside the visible tumor borders. The tumor's own vessels expand significantly, their number increases. The presence of a triad of signs - increased pigmentation, vascularization of the nevus and blurred borders - allows differentiating the true profession of the tumor from its increase due to reactive hyperplasia of the epithelium. Limitation of nevus displacement in relation to the sclera is a late symptom indicating the development of melanoma. Borderline nevus is more often diagnosed in children, mixed nevus, especially localized in the area of the lacrimal caruncle, - in adults. Treatment - excision of the nevus - is indicated when signs of its growth appear. According to the latest data, the incidence of malignant transformation of conjunctival nevi reaches 2.7%.

Blue (cellular) nevus of the conjunctiva is a congenital formation that is extremely rare. It is considered one of the symptoms of systemic skin lesions of the oculodermal region. With a blue nevus, the conjunctiva of the eyeball, unlike the skin, is colored brown. The formation is flat, reaches large sizes, does not have a clear shape, but its borders are well defined. Blue nevus can be combined with melanosis. Treatment is not required, since malignant variants of blue nevus in the conjunctiva have not been described.

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Primary acquired conjunctival melanosis

Primary acquired melanosis (PAM) of the conjunctiva is usually unilateral. The tumor occurs in middle age; it can be localized in any part of the conjunctiva, including the fornices and palpebral part. As primary acquired melanosis grows, new pigmentation zones typically appear. The foci of primary acquired melanosis are flat, with fairly clear boundaries, and have an intensely dark color. Reaching the limbus, the tumor easily spreads to the cornea. Treatment involves wide laser coagulation or electroexcision of the tumor with preliminary applications of 0.04% mitomycin C solution. Cryodestruction gives good results with a small spread of primary acquired melanosis. Brachytherapy is more effective in cases of damage to the fornices and tarsal conjunctiva. The prognosis is unfavorable, since in 2/3 of cases primary acquired melanosis undergoes malignancy.