title: Benign pineal cysts in children with bilateral retinoblastoma: a new variant of trilateral retinoblastoma?
abstract: OBJECTIVE
  Patients with hereditary retinoblastoma (Rb) develop in 4%-8% a malignant midline tumor called trilateral Rb (TRb). We report in this study on benign pineal cysts observed in patients investigated for TRb.
  
  
  METHODS
  Between September 1990 and December 2001, 172 patients were screened for TRb. Ninty-five had bilateral, 77 unilateral disease. The median age at diagnosis of Rb was 7 months (range 1-26). Treatment included enucleation, local treatment with cryotherapy or photocoagulation, first-line chemotherapy (CT), thermo-chemotherapy (TCT), Ruthenium plaque, and, rarely, external beam radiation (EBR).
  
  
  RESULTS
  TRb was found in 5/95 patients (5.3%) with bilateral disease. Interestingly, five other patients (5.3%) presented a pineal cyst on magnetic resonance imaging (MRI). No cysts were recorded in the 77 patients with unilateral disease. This difference was statistically significant (P < 0.05). The median age at diagnosis of the pineal cyst was 26 months (range 16-80), much younger than reported in literature for healthy children. Four of five patients with TRb died of the disease, while all the patients with pineal cysts remained stable and asymptomatic during a median follow-up of 41 months (range 37-54).
  
  
  CONCLUSIONS
  This report describes benign cystic lesions of the pineal gland in patients with hereditary Rb, suggesting a benign variant of TRb. Underlying possible pathogenetic mechanisms are discussed.
authors: Pediatric Hematology-Oncology Unit, University Hospital, Lausanne, Switzerland. Maja.Beck-Popovic@hospvd.ch
authors: Maja
authors: M
authors: Beck Popovic
authors: Aubin
authors: A
authors: Balmer
authors: Philippe
authors: P
authors: Maeder
authors: Teresa
authors: T
authors: Braganca
authors: Francis L
authors: FL
authors: Munier
mesh_terms: D001932:Brain Neoplasms / Q000209:etiology / Q000473:pathology; D020863:Central Nervous System Cysts / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology*; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D010870:Pineal Gland; D010871:Pinealoma / Q000209:etiology / Q000473:pathology; D011379:Prognosis; D019572:Retinal Neoplasms / Q000150:complications*; D012175:Retinoblastoma / Q000150:complications*; D013557:Switzerland / Q000453:epidemiology; D014057:Tomography, X-Ray Computed