| Abstract: |
The term trilateral retinoblastoma (TRB) classically refers to the association of bilateral intraocular retinoblastoma with a pineoblastoma, a primitive neuroectodermal tumor that arises in the pineal gland. The link between intraocular retinoblastoma and an ectopic, intracranial malignancy was first recognized in 1977 by Jakobiec and colleagues [1]. In 1980, Bader et al reported a series of 10 children with bilateral RB who developed another primary malignancy in the pineal gland, and the term trilateral RB was associated with this diagnosis [2]. Histopathologically, the intracranial tumor in TRB resembles primitive neuroectomal tumors (PNET), with varying degrees of neuronal and photoreceptor differentiation. One explanation for the development of TRB is that the retina and the pineal gland have a common embryologic origin, and there may be vestigial photoreceptor elements in the pineal gland. In lower animals, the pineal gland functions as a photoreceptor organ and is sometimes referred to as the “third eye.” In the literature, there is some dispute regarding the cell of origin for TRB, and more recent studies suggest that the tumor may arise from the germinal layer of primitive cells (subependymal plate) rather than the pineal gland [3, 4]. For that reason, some authors refer to the intracranial tumor in retinoblastoma patients as a pineal neuroblastic tumor (PNT) rather than a pineoblastoma [5]. © Springer-Verlag Berlin Heidelberg 2015. All rights reserved. |
