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Retinoblastoma is the most common primary intraocular tumor of childhood and may be heritable or occur sporadically. Anterior diffuse retinoblastoma is an uncommon variant that is thought to be sporadic. We describe a child with anterior diffuse retinoblastoma who presented with a pseudohypopyon. Genetic analysis showed a germline mutation of the RB1 allele that is potentially heritable. Immunofluorescence staining was positive for transforming growth factor beta and for vascular endothelial growth factor and negative for inducible nitric oxide synthase and for hypoxia inducible factor alpha in the tumor seeds, indicating acquisition of nonischemia-mediated survival factors of the tumor seeds in the aqueous humor.
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 (Table). 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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