disturbance in axoplasmic flow. Thirty percent of eyes have sheathing of retinal blood vessels overlying­

the tumor, and 10% have mild degrees of peripapillary subretinal fluid (Fig. 5.20). A disc melanocytoma may occasionally reveal only mild-to-moderate pigmentation, and uveal melanocytomas away from the optic nerve may have a wide variation in pigmentation­ . These changes complicate diagnostic differentiation.

Melanocytoma in the papillary region must be distinguished from hyperplastic, hamartomatous, or neoplastic growths of the peripapillary pigment epithelium, as well as from uveal melanomas arising in the region of the optic disc. Choroidal malignant melanomas are rarely arising as primary tumors of the optic disc. It appears as a dark mass in the nerve head that is very similar to melanocytoma [151]. Juxtapapillary choroidal melanomas are not uncommon. The diffuse variant of choroidal melanoma has a morked tendency to actively invade optic nerve. It may grow over the disc and project anteriorly into the vitreous or posteriorly through the lamina cribrosa. This is an important tumor in the differential diagnosis of melanocytoma [152].

5.7.5  Treatment

Since this is a benign lesion, no treatment is indicated. Careful documentation of the size and location should be performed. Follow-up intervals of 6–12 months initially are indicated to establish the benign static nature of the growth. If rapid growth occurs, then consideration of choroidal melanoma or other neoplastic disease must be entertained.

5.8  Metastatic Tumors: Leukemia

5.8.1  Introduction

Metastatic cancer to the eye is most frequently found in the choroid but can occur in the optic disc. Breast and lung carcinomas are the most frequently encountered [153] but are very rare in pediatric population.

However, leukemic infiltration of the optic disc is commonly seen in children. In histopathologic study, Allen and Straatsma [154] noted ocular involvement in 50% of patients who died with leukemia. The acute forms affected the eye 4 times more frequently than the chronic types, and the optic nerve was affected in 34% of ocular leukemia cases.

Fig. 5.20  Optic disc dursen. Multiple lumps on disc surface with a mulberry appearance. Note absence of the cup. The lumps will autofluorescence if a light is placed adjacent to the disc

Leukemia infiltration of the optic nerve initially presents as a swollen optic disc. It is often pale gray, and hemorrhages may also be present; subretinal