The Epidemiology of Primary Central Nervous System Tumors at the National Neurologic Institute in Saudi Arabia: A Ten-Year Single-Institution Study.

OBJECTIVES: This study is aimed at describing the epidemiological trends of primary CNS tumors in children and adults at the National Neurologic Institute in Saudi Arabia. METHODS: A retrospective epidemiological approach was used where data was obtained from the department of pathology registry files and pathology reports. The records of all patients registered from January 2005 to December 2014 with a diagnosis of primary CNS tumor (brain and spinal cord) were selected. Data about sex, age, tumor location, and histologic type were collected. The classification was based on the International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3). RESULTS: Nine hundred and ninety-two (992) cases of primary CNS tumors throughout the ten years (2005 to 2014) were reviewed. There were 714 (71.97%) adults and 278 (28.02%) in the pediatric age group. Nonmalignant tumors dominated the adult population (60.08%) while malignant tumors were more frequent in the pediatric population. Gliomas constituted the most common neoplastic category in children and adults. The most common single tumor entity was meningioma (26.99%, ICD-O-3 histology codes 9530/0, 9539/1, and 9530/3). Medulloblastomas (ICD-O-3 histology codes 9470, 9471, and 9474) were the most common single tumor entity in the pediatric age group (26.62%). CONCLUSIONS: This is an institution-based, detailed, and descriptive epidemiological study of patients with primary CNS tumors in Saudi Arabia. In contrast to other regional and international studies, the medulloblastomas in our institution are more frequent than pilocytic astrocytomas. Limitations to our study included the referral bias and histology-based methodology.

Whole slide imaging compared with light microscopy for primary diagnosis in surgical neuropathology: a validation study.

BACKGROUND: Digital pathology practice is rapidly gaining popularity among practicing anatomic pathologists. Acceptance is higher among the newer generation of pathologists who are willing to adapt to this new diagnostic method due to the advantages offered by whole slide imaging (WSI) compared to traditional light microscopy (TLM). We performed this validation study because we plan to implement the WSI system for diagnostic services. OBJECTIVES: Determine the feasibility of using digital pathology for diagnostic services by assessing the equivalency of WSI and TLM. DESIGN: A laboratory-based cross-sectional study. SETTING: Central laboratory at a tertiary health care center. MATERIALS AND METHODS: Four practicing surgical pathologists participated in this study. Each pathologist blindly reviewed 60 surgical neuropathology cases with a minimum 8-week washout-period between the two diagnostic modalities (WSI vs. TLM). Intraobserver concordance rates between WSI and TLM diagnoses as compared to the original diagnosis were calculated. MAIN OUTCOME MEASURES: Overall intraobserver concordance rates between each diagnostic method (WSI and TLM) and original diagnosis. SAMPLE SIZE: 60 in-house surgical neuropathology cases. RESULTS: The overall intraobserver concordance rate between TLM and original diagnosis was 86.3% (range 76.7%-91.7%) versus 80.8% for WSI (range 68.3%-88.3%). These findings are suggestive of the superiority of TLM, but the Fleiss' Kappa statistic indicated that the two methods are equivalent, despite the low level of the K value. CONCLUSION: WSI is not inferior to the light microscopy and is feasible for primary diagnosis in surgical neuropathology. However, to ensure the best results, only formally trained neuropathologists should handle the digital neuropathology service. LIMITATIONS: Only one diagnostic slide per case rather than the whole set of slides, sample size was relatively small, and there was an insufficient number of participating neuropathologists. CONFLICT OF INTEREST: None.

Differential diagnosis between pancreatic neuroendocrine and solid pseudopapillary neoplasms on endoscopic ultrasound-guided fine-needle aspiration. An immunohistochemical study.

OBJECTIVES: To evaluate the role of applying a limited panel of immunohistochemical stains on the cellblock preparation from samples obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the aim of differentiating solid pseudopapillary neoplasms (SPNs) from neuroendocrine tumors (NETs).  METHODS: We retrospectively retrieved all the EUS-FNAs of the pancreas that have a diagnosis of NET or SPN that were performed at 2 tertiary care hospitals in Riyadh, Kingdom of Saudi Arabia from May 2004 to December 2014. Diff-Quik, Papanicolaou, and Immunohistochemistry stains on cellblock preparations were performed.   RESULTS: Twenty cases were available (16 pancreatic neuroendocrine tumors (pNETs) and 4 SPNs). The pNETs were immunoreactive for synaptophysin, chromogranin A and CD56 while E-cadherin was diffusely to focally cytoplasmic positive. ß-catenin was negative or showed focal cytoplasmic immunoreactivity. In comparison, SPNs were positive for vimentin, CD10, CD-56, focally positive for progesterone receptors and synaptophysin, and revealed nuclear immunostaining for ß-catenin. They were negative for chromogranin A and E-cadherin.  CONCLUSION: Based on EUS-FNA samples, nuclear immunoreactivity for ß-catenin with loss of membranous immunostaining for E-Cadherin can potentially facilitate differentiating SPNs from pNETs.