Bumps on the Iris

The Problem

“My child has bumps on the colored part of the eye.”

Common Causes

Small iris cysts at the pupillary border

Lisch nodules

Iris nevi

Other Causes

Large iris cysts

Congenital iris ectropion

Intraocular tumor (diktyoma)

Iris mammillations

Juvenile xanthogranuloma

KEY FINDINGS

History

Small lesions on the iris are usually asymptomatic and do not affect vision. A history of eye pain, corneal clouding, or

decreased vision suggests a possible tumor. Juvenile xanthogranuloma (JXG) may be associated with small orange-brown papules on the head or face. Iris JXG lesions may bleed, and the resultant hyphema may cause ocular pain.

Examination

Without a slit lamp, evaluation of iris lesions may be difficult, particularly in a noncooperative toddler. Some lesions may be visible with a penlight. Benign iris cysts are often seen best by examining the pupil margin when evaluating the red reflex with a direct ophthalmoscope.

WHAT SHOULD YOU DO?

Small irregular lesions at the pupil margin in an infant do not require further evaluation. Small iris nevi are common and also do not require evaluation unless abnormal growth occurs. Children with other iris abnormalities should be referred to a pediatric ophthalmologist.

Lisch nodules are almost pathognomonic of neurofibromatosis, and evaluation for other abnormalities associated with neurofibromatosis should be performed.

What Shouldn’t Be Missed

Although extremely rare, large iris cysts or iris distortion due to intraocular tumors (diktyoma) may cause

glaucoma, eye pain, redness, and corneal clouding. This requires immediate evaluation.

COMMON CAUSES

1.Iris cysts. Cysts of the iris are not common, but may occur in otherwise normal children. Small, scalloped irregularities at the pupil margin are almost always benign (Figure 17–1). Large iris cysts are very rare. They may cause vision loss (Figure 17–2).

2.Lisch nodules. Lisch nodules almost always occur in children with neurofibromatosis. They are usually not present in infancy. The

incidence and number of lesions increase with age. By age 20, more than 95% of patients with neurofibromatosis have Lisch nodules. Lisch nodules are small, tan, and slightly elevated from the iris surface (Figure 17–3A and B). The Lisch nodules do not cause any vision problems. They play an important role in establishing a diagnosis.

3.Iris nevi. Iris nevi present as areas of irregular pigment on the surface of the iris. They are most easily noticed when the nevi are brown and the underlying iris pigment is fair (Figure 17–4). These are flat (rather than elevated like Lisch nodules), but this feature cannot be accurately assessed without a slit lamp. Iris nevi in children are almost always benign.

B

FIGURE 17–3 ■ (A and B) Lisch nodules in patients with neurofibromatosis. They appear as small, tan mounds of tissue on the iris surface. Lisch nodules increase in number with age.

FIGURE 17–2 ■ Large iris cyst obstructing pupil. A cataract is also present (arrow). The irregular vertical line is the slit beam, which is distorted superiorly by the cyst.

APPROACH TO THE PATIENT

Iris lesions in infants and young children are uncommon, and they are usually benign (Table 17–1). From a practical standpoint, they may be easily missed because of their small size and the difficulty examining an active young child.

History

Bumps on the iris may be brought to your attention by the parents, or may be noticed during a well-child check. If the parents have noticed them, they should be asked when the bumps were first identified, and whether they have changed in size or shape. General questions about vision and any associated ocular symptoms should be asked. If Lisch nodules are suspected, a family history of neurofibromatosis may be present, and

the child’s development may be delayed. If an iris nevus is present, questions should be asked about a family history of multiple nevi or skin cancer (e.g., dysplastic nevus syndrome).

JXG may present as an elevated orange-brown lesion of the iris, which may bleed and cause a hyphema. The lesion may be isolated to the iris, or be associated with small papular lesions of the head and neck.

Examination

The child’s vision should be checked using ageappropriate methods. A penlight should be used to assess the iris. In addition to the lesions themselves, the examiner should check the pupillary reactions and look for irregularities of the iris. Small iris cysts at the pupil margin are often best visualized by examining the red reflex with a direct ophthalmoscope.

Iris nevi are relatively common. They appear as flat areas of pigmentation that are distinct from the underlying iris. They are usually discrete, but sometimes cover a large portion of the iris (Figure 17–4).

Large cysts of the iris are rare, and ciliary body tumors are even rarer. These may appear as elevated iris irregularities. If they produce glaucoma, corneal clouding and light sensitivity may be present.

If Lisch nodules are suspected, the child should be checked for café-au-lait spots, axillary freckling, and other systemic manifestations of neurofibromatosis.

Table 17–1.

Causes of Iris Lesions in Children

■Iris cyst

■JXG

■Lisch nodules

■Iris nevi

PLAN

Small, scalloped irregularities of the pupil margin in an infant do not require additional evaluation. Infants with other iris lesions should be referred to an ophthalmologist (Figure 17-5). Children with Lisch nodules should be evaluated for other stigmata of neurofibromatosis. Iris nevi are almost always benign in children. However, like skin nevi, they should be monitored for abnormal growth. Large iris lesions are rare, but they should be evaluated by an ophthalmologist (Figure 17-6).

WHAT SHOULDN’T BE MISSED

Patients with significant iris lesions, such as large cysts or possible ciliary body tumor, should be referred for prompt ophthalmic evaluation. The presence of Lisch nodules strongly suggests a diagnosis of neurofibromatosis, and confirmatory evaluation is indicated.

When to Refer

■Small scalloped lesions at the pupil margin do not require referral

■The iris should be evaluated in patients who have other findings suggestive of neurofibromatosis

■Patients with iris nevi should be referred if the lesions are changing

■Patients with large cysts or other iris abnormalities should be referred