From Counting Mitoses to Ki67 Assessment: Technical Pitfalls in the New WHO Classification of Endocrine and Neuroendocrine Tumors

Author(s):  
Ian A. Cree
2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 4129-4129 ◽  
Author(s):  
Jean-Yves Scoazec ◽  
Anne Couvelard ◽  
Genevieve Monges ◽  
Emmanuelle Leteurtre ◽  
Genevieve Belleannee ◽  
...  

4129 Background: In contrast to the 2000 World Health Organization (WHO) classification of digestive neuroendocrine tumors (NET) in which morphologic differentiation was the first criterion, the 2010 WHO classification of NET is based mostly on histologic grade. NET are now classified into three main categories: NET G1 (mitotic count <2/10 HPF and/or ≤2% Ki67 index), NET G2 (2-20/10 HPF and/or 3-20%), and neuroendocrine carcinoma (NEC) of small or large cell type. While NET G1 and G2 are well-differentiated tumors, NEC are considered poorly differentiated G3 tumors. We looked at the agreement between grade and differentiation to determine whether all NET can be readily classified according to the 2010 WHO classification. Methods: We designed a 1-year prospective, epidemiologic study to assess the characteristics of newly diagnosed NET, including diagnostic pathology. From August 2010 to July 2011, all pathology laboratories in France were invited to register all incident cases of gastroenteropancreatic (GEP) and thoracic NET, excluding small cell carcinoma. For GEP-NET, investigators were asked to indicate morphologic differentiation (according to WHO 2000) and elements of histologic grade (mitotic index, Ki67 index), according to ENETS. Results: Of 500 invited centers, 80 participated; 1417 incidental cases were included and 77 excluded (duplicates or exclusion criteria), totaling 1340 cases; 778 (58.1%) were GEP-NET; 660/778 (85%) were well differentiated, 72 (9%) poorly differentiated, and 46 (6%) adenocarcinoid, nonclassified, or not evaluable; 422 (54.2%) were G1, 220 (28%) G2, 104 (13.5%) G3, and 32 (4.1%) had missing grades. Of those deemed G3, 72 (69%) were described as poorly differentiated, 21 (20%) as well differentiated (mean Ki67 index 35%, range 25%-60%), and 11 (10.5%) as adenocarcinoid. Conclusions: In this prospective, epidemiologic study, overall agreement between grade and differentiation was good. However, a significant proportion of G3 NET were classified as well differentiated and thus unclassifiable by 2010 WHO classification. This group of tumor deserves to be included in future classifications to help the clinician decide whether they should be treated as NET G1/G2 or NEC G3.


Pathology ◽  
2021 ◽  
Vol 53 ◽  
pp. S57
Author(s):  
Z.-L. Chow ◽  
V.A. White ◽  
B.I. Indave ◽  
D. Lokuhetty ◽  
I.A. Cree

Author(s):  
Keisuke Miyake ◽  
Kenta Suzuki ◽  
Tomoya B Ogawa ◽  
Daisuke Ogawa ◽  
Tetsuhiro Hatakeyama ◽  
...  

Abstract Background The molecular diagnosis of gliomas such as isocitrate dehydrogenase (IDH) status (wild-type [wt] or mutation [mut]) is especially important in the 2016 WHO classification. Positron emission tomography (PET) has afforded molecular and metabolic diagnostic imaging. The present study aimed to define the interrelationship between the 2016 WHO classification of gliomas and the integrated data from PET images using multiple tracers, including 18F-fluorodeoxyglucose ( 18F-FDG), 11C-methionine ( 11C-MET), 18F-fluorothymidine ( 18F-FLT), and 18F-fluoromisonidazole ( 18F-FMISO). Methods This retrospective, single-center study comprised 113 patients with newly diagnosed glioma based on the 2016 WHO criteria. Patients were divided into four glioma subtypes (Mut, Codel, Wt, and glioblastoma multiforme [GBM]). Tumor standardized uptake value (SUV) divided by mean normal cortical SUV (tumor-normal tissue ratio [TNR]) was calculated for 18F-FDG, 11C-MET, and 18F-FLT. Tumor-blood SUV ratio (TBR) was calculated for 18F-FMISO. To assess the diagnostic accuracy of PET tracers in distinguishing glioma subtypes, a comparative analysis of TNRs and TBR as well as the metabolic tumor volume (MTV) were calculated by Scheffe’s multiple comparison procedure for each PET tracer following the Kruskal–Wallis test. Results The differences in mean 18F-FLT TNR and 18F-FMISO TBR were significant between GBM and other glioma subtypes (p &lt; 0.001). Regarding the comparison between Gd-T1WI volumes and 18F-FLT MTVs or 18F-FMISO MTVs, we identified significant differences between Wt and Mut or Codel (p &lt; 0.01). Conclusion Combined administration of four PET tracers might aid in the preoperative differential diagnosis of gliomas according to the 2016 WHO criteria.


Author(s):  
Elisabeth J. Rushing

SummaryIdentification of the underlying genetic and epigenetic alterations in an increasing number of tumors of the nervous system is contributing to a more clinically relevant classification. In the following article, the 7 cIMPACT-NOW publications, which adumbrate the upcoming 5th edition of the WHO Classification of Tumours of the Central Nervous Sytem are summarized.


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