There is little published information about scleral invasion in retinoblastoma. Most recent studies included fewer than 20 patients. We were able to find only 3 studies including more than 10 patients who provided survival data.5,12,17 Twenty-one of 32 patients were disease free in the Stannard et al study12 dealing with patients treated from 1952 to 1975 and 7 of 14 were disease free in the Khelfaoui et al study5 including patients treated from 1977 to 1990. More recently, Antoneli et al17 reported 14 patients with microscopic scleral invasion and the probability of 3-year survival was 58%. However, their survival results were analyzed together with patients with overt orbital extension. Therefore, with a survival rate of 77%, our results compare favorably with those series. Given the lack of information on this population, many questions about their management, such as the need for adjuvant therapy for those with only intrascleral invasion, the type of chemotherapy to be given, and the need for orbital radiotherapy, remain controversial.4,9,10,18 Our series, including 32 patients with microscopic scleral invasion, uniformly staged and treated under prospective treatment protocols, provides information on these issues, but only a multicentric study including more patients could provide a definitive answer to some of these questions. Our study showed that microscopic scleral invasion is an uncommon feature in patients with retinoblastoma in our setting. As reported previously, it tended to occur together with other major pathological risk factors, such as PLONI, reflecting aggressive disease probably due to late diagnosis.9,13 However, since only a limited area of the enucleated eye is sampled for pathological examination, microscopic scleral invasion or other pathological risk factors may be missed in some cases, even when a comprehensive pathological examination is done; the true incidence of these features may be higher.