Multinational Retrospective Central Pathology Review of Neuroblastoma: Lessons Learned to Establish a Regional Pathology Referral Center in Resource-Limited Settings

Context.— Several countries of the Central America and Caribbean region have been sharing regional neuroblastoma (NB) treatment guidelines. However, there is no standardization in the diagnosis, subclassification, or tumor biology to aid in the risk stratification of these patients. Objective.— To examine the histology and assess the accuracy of the local pathology reports; to evaluate the usefulness of manual MYCN immunohistochemistry (IHC); and to use NB as a model to identify the needs to establish a central pathology review (CPR) program in this region. Design.— A retrospective CPR of specimens derived from patients with a diagnosis of NB and treated under the regional NB guidelines between 2012 and 2017 was conducted, allowing for a comparison between local diagnoses and the CPR diagnoses. Manual MYCN IHC was performed in the confirmed NB specimens and the results compared with known fluorescence in situ hybridization or automated IHC results, when available. Results.— The 156 specimens reviewed included 460 blocks and 183 original slides. Neuroblastoma was confirmed in 138 samples (88.5%), but low concordance rates for Shimada classification (n = 39; 25.0%), mitotic-karyorrhectic index (n = 4; 2.5%), and International Neuroblastoma Pathology Classification (n = 18; 11.5%) were noted. Manual MYCN IHC done in 120 specimens showed conclusive results in 89.2% (28 positive, 23.4%; 79 negative, 65.8%) and questionable results in 10.8% (n = 13). Conclusions.— This retrospective CPR highlights the need for a CPR program to serve this region, to ensure correct diagnosis and subclassification of NB, and to provide manual MYCN IHC—with reflexing to fluorescence in situ hybridization, if questionable. This approach can further regional collaboration, enhance test utilization, and ultimately improve patients' outcomes.