Benign pineal cysts in children with bilateral retinoblastoma: a new variant of trilateral retinoblastoma?
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.
Beck Popovic
Maja
M
Pediatric Hematology-Oncology Unit, University Hospital, Lausanne, Switzerland. Maja.Beck-Popovic@hospvd.ch
Balmer
Aubin
A
Maeder
Philippe
P
Braganca
Teresa
T
Munier
Francis L
FL
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