Session Title: Miscellaneous
Session Date/Time: Saturday 13/09/2014 | 11:00-13:00
Paper Time: 11:00
Venue: Boulevard E
First Author: : N.Vilà CANADA
Co Author(s): : P. Zoroquiain V. Bravo-Filho P. Logan M.N. Burnier
Primary intraocular lymphoma (PIOL) is characterized by bilateral ocular involvement simulating uveitis (masquerade syndrome), which, by multi-centricity, involves the central nervous system (CNS). On the other hand, primary CNS lymphoma (PCNSL) can originate in the brain, spinal cord, leptomeninges, and eyes. PCNSL typically remains confined to the CNS, but approximately 15% of patients develop intraocular lymphoma. Conversely, 65–90% of PIOL patients develop PCNSL. The purpose of this study is to compare the immune-expression of PCNA and DNA flow cytometry in PIOLs and PCSNLs.
Henry C. Witelson Ocular Pathology Laboratory – Department of Ophthalmology (McGill University)
Twenty-two formalin-fixed, paraffin-embedded specimens (11 PIOLs and 11 PCNSLs) were immunostained with a monoclonal antibody against PCNA. A PCNA grading system of 0, +, and ++ was applied to evaluate the intensity of the immunostain. Furthermore, the percentage of PCNA stained cells was determined in ten high power fields and recorded as low (less than 30%), medium (from 30% to 70%), and high (more than 70%). In addition, all specimens were analyzed using DNA flow cytometry to measure the S-phase fraction (SPF) of the tumors.
All tumors expressed PCNA. There was a significant difference in the intensity of staining between the two groups; all of them had areas with + and ++ staining. In the CNSL group, there were 2 cases with high number of PCNA positive cells (70%), 3 with medium (50%) and 6 with low (20%). In the PIOL group, 7 cases were graded as high (70%) , 3 cases with medium (50%) and 1 was low (20%). The SPF average was higher in the PIOL group (34%) than in the PCNSL group (18%).
Although PCNSLs are a more lethal tumor than PIOLs, the current study shows that PIOLs have more actively dividing cells based on SPF fraction analysis. This finding suggests that these tumors might constitute different types or classes of extra-nodal B cell lymphomas. Furthermore, the lethality of the PCNSL might be a consequence of its location, and not a result of more aggressive neoplastic cells.