Anterior Diffuse Retinoblastoma Mutational Analysis and Immunofluorescence Staining Anterior Diffuse Retinoblastoma Mutational Analysis and Immunofluorescence Staining Michelle B by ProQuest


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									                               Anterior Diffuse Retinoblastoma
                        Mutational Analysis and Immunofluorescence Staining
         Michelle B. Crosby, MD, PhD; G. Baker Hubbard, MD; Brenda L. Gallie, MD; Hans E. Grossniklaus, MD, MBA

● Retinoblastoma is the most common primary intraocular                   changes in color of the left eye during the preceding 2 months.
tumor of childhood and may be heritable or occur sporad-                  Examination showed 20/20 vision in the right eye and 20/60
ically. Anterior diffuse retinoblastoma is an uncommon var-               vision in the left eye. The intraocular pressures were 16 and 34
                                                                          mm Hg in the right and left eyes, respectively. Examination
iant that is thought to be sporadic. We describe a child
                                                                          showed a normal right eye. Anterior segment examination
with anterior diffuse retinoblastoma who presented with a                 showed a pseudohypopyon in the left eye (Figure 1). Dilated fun-
pseudohypopyon. Genetic analysis showed a germline mu-                    dus examination showed a possible small, inferior, peripheral
tation of the RB1 allele that is potentially heritable. Im-               mass in her left retina. An anterior-chamber fine-needle aspira-
munofluorescence staining was positive for transforming                    tion biopsy showed a small, round blue cell tumor, consistent
growth factor and for vascular endothelial growth factor                  with retinoblastoma (Figure 2, A and B). Complete blood cell
and negative for inducible nitric oxide synthase and for                  count and bone marrow biopsy were performed, and findings
hypoxia inducible factor in the tumor seeds, indicating                   from both were normal. The left eye was enucleated. Mutational
acquisition of nonischemia-mediated survival factors of the               analysis of the patient’s tumor showed 2 RB1 mutant alleles: a
tumor seeds in the aqueous humor.                                         nonsense mutation c.763C → T(R255X) and a deletion,
                                                                          c.1572delA. The nonsense mutation was also identified in the
   (Arch Pathol Lab Med. 2009;133:1215–1218)                              DNA from the patient’s blood, indicating a germline mutation

R   etinoblastoma is the most common primary intraocu-
      lar tumor in childhood. When a family history is
present, 50% of offspring of a parent carrying an RB1 mu-
                                                                                           PATHOLOGIC FINDINGS
                                                                             Gross examination of the enucleated eye showed white
tant allele will inherit that allele; 40% of them will develop            material in the anterior chamber. Similar white material
retinoblastoma tumors. Each tumor that forms will have                    was present anterior to the vitreous base and extended
lost the second RB1 allele. Diffuse anterior retinoblastoma               circumferentially for 360 (Figure 3, A). A small, white
presents in older children and may mimic uveitis because                  tumor was present in the peripheral retina near the ora
it presents as cells in the posterior compartment and an-                 serrata inferiorly. Scattered retinal hemorrhages with
terior chamber without an obvious retinal mass. Diffuse                   white centers were present (Figure 3, B and C). Micro-
anterior retinoblastoma has previously been described as                  scopic examination showed fibrovascular tissue on the an-
occurring in sporadic mutations. Herein, we report on a                   terior surfaces of the iris leaflets causing ectropion uveae.
patient with diffuse anterior retinoblastoma who is the                  
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