C. Gailloud

Cobalt-60 Treatment of Choroidal Hemangiomas

PURPOSE We investigated the therapeutic possibilities of gamma brachytherapy to improve the final functional results of eyes with choroidal hemangiomas, which are benign vascular tumors that can induce progressive impairment of visual acuity. METHODS We treated 41 patients with choroidal hemangioma with cobalt-60 applicators. The lesions consisted of 39 circumscribed hemangiomas and two diffuse hemangiomas in patients with Sturge-Weber syndrome. Before treatment, visual acuity in the affected eye was 20/200 in ten patients, 20/200 to 20/50 in 17 patients, 20/40 to 20/25 in 11 patients, and 20/20 in three patients. All patients were symptomatic. The macula was infiltrated by the tumor in 12 eyes (29.3%). There was retinal detachment in 40 eyes (97.6%), cystoid edema in ten eyes (24.4%), subretinal fibrosis in eight eyes (19.5%), and areolar atrophy in two eyes (4.9%). RESULTS After treatment, the retina was reattached in all eyes, and the tumor progressively transformed into a flat scar. The postirradiation macular lesions that we identified were pigment migrations in the macular region, subretinal fibrosis, and an areolar atrophic scar. We correlated the functional results at two, five, and ten years after treatment with the initial visual acuity, and with pre-existing and posttreatment macular lesions. CONCLUSIONS Our results suggest that radiotherapy is a valuable therapeutic modality for choroidal hemangiomas, particularly in hemangiomas that involve the macula, and for tumors associated with bullous retinal detachment.

Paternal selection favoring mutant alleles of the retinoblastoma susceptibility gene

SummaryPenetrance and segregation rates of mutant Rb-1 alleles were assessed in all 51 members of eight kindreds with hereditary retinoblastoma by concomitant ophthalmologic examination and determination of seven intragenic restriction fragment length polymorphisms (RFLPs). Penetrance was in the range reported in the literature except for one family in which it was only 42.8%. However, the odds of transmitting a mutant Rb-1 allele from one generation to the next were 25∶9 in this population, much above the Mendelian 1∶1 ratio (P < 0.025). This preferential transmission was discovered through the use of molecular information. Further analysis revealed that this distortion was due to preferential inheritance among children of male carriers (18∶4, P < 0.005). No difference from a 1∶1 segregation ratio could be detected among the children of female carriers (7∶5). These findings were consistent with a review of relevant data in the literature.

Constitutional Karyotype in Retinoblastoma Case Report and Review of Literature

High resolution karyotype was performed in 13 retinoblastoma patients. A mosaic pattern for del(13)(q14.1;q14.3) was found in a girl with sporadic bilateral retinoblastoma and midface dysmorphism. In addition, 162 cases of 13q aberrations were reviewed, including 140 retinoblastoma patients and 22 non-penetrance 13q14 deletions. Some epidemiological and genetic involvements are discussed.

Radial asymmetry in the topography of retinoblastoma Clues to the cell of origin

Retinoblastoma is a malignancy of the human developing retina. In situ as well as in vitro studies have attributed tumoral histogenesis either to a primitive retinoblast with neuronal and glial differentiation potentials, or to a photosensory progenitor cell. Here it is shown in vivo that the retinal topography of 457 retinoblastoma and retinoma foci is radially asymmetrical. Tumor density appears to mimic the horizontal visual streak characteristic of red/green cone cell distribution. Such a non-random distribution seems to invalidate the hypothesis of a primitive multipotential neuroblast as the unique source of retinoblastoma and may support the view that retinoblastoma evolves along the cone cell lineage.

Proton Beam Irradiation of Choroidal Melanomas at the PSI: Technique and Results

The aim of radiotherapy is to sterilize all cells of a tumor with minimal damage to surrounding normal cells. By using a high energy proton beam for the irradiation of ocular tumors, one comes close to achieving this goal: protons penetrating tissue lose their energy by ionization in such a manner that the energy loss rises by a factor 3–4 just before a sharp stop (the Bragg peak). The scattering of protons within the tissue is much smaller than with usual radiations. The sharp stop in the Bragg peak allows matching of the depth of the irradiated volume to the depth of the tumor in the eye by adjusting the proton range in the tissue. The low scattering of protons allows the irradiated volume to be limited laterally by the use of a collimator which is shaped to the profile of the tumor to be irradiate.

Retinoblastoma: Unusual Warning and Clinical Signs

Three clinical cases have been chosen to illustrate the pitfalls that can be encountered when warning signs other than leukokoria or strabismus indicate possible retinoblastoma. The first case, a four-year-old boy, was admitted to hospital after an accident, presenting uveitis, glaucoma and a subluxated lens. He was suffering from unilateral retinoblastoma, already exteriorized and the cause of death some months later. The second case, and 11-month-old female child was seen on fundus examination to present a yellowish elevated calcified mass which turned out to be tuberous sclerosis. The third patient, a 43-year-old male, father of two children suffering from retinoblastoma, was found on routine examination to be carrying a partially-calcified retinal tumour. Subsequent haemorrhaging rendered enucleation necessary and microscopic examination confirmed the diagnosis of retinoma. The diagnosis of retinoblastoma should always be kept in mind whenever an intraocular mass is revealed or where there are unexplained atypical ocular signs.