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Research article - Peer-reviewed, 2021

Mitotic Figures-Normal, Atypical, and Imposters: A Guide to Identification

Donovan, Taryn A.; Moore, Frances M.; Bertram, Christof A.; Luong, Richard; Bolfa, Pompei; Klopfleisch, Robert; Tvedten, Harold; Salas, Elisa N.; Whitley, Derick B.; Aubreville, Marc; Meuten, Donald J.


Counting mitotic figures (MF) in hematoxylin and eosin-stained histologic sections is an integral part of the diagnostic pathologist's tumor evaluation. The mitotic count (MC) is used alone or as part of a grading scheme for assessment of prognosis and clinical decisions. Determining MCs is subjective, somewhat laborious, and has interobserver variation. Proposals for standardizing this parameter in the veterinary field are limited to terminology (use of the term MC) and area (MC is counted in an area measuring 2.37 mm(2)). Digital imaging techniques are now commonplace and widely used among veterinary pathologists, and field of view area can be easily calculated with digital imaging software. In addition to standardizing the methods of counting MF, the morphologic characteristics of MF and distinguishing atypical mitotic figures (AMF) versus mitotic-like figures (MLF) need to be defined. This article provides morphologic criteria for MF identification and for distinguishing normal phases of MF from AMF and MLF. Pertinent features of digital microscopy and application of computational pathology (CPATH) methods are discussed. Correct identification of MF will improve MC consistency, reproducibility, and accuracy obtained from manual (glass slide or whole-slide imaging) and CPATH approaches.


mitotic figure; mitotic count; MC; prophase; prometaphase; metaphase; anaphase; telophase; computational pathology; CPATH; artificial intelligence; AI; whole slide image; WSI; pathology; oncology

Published in

Veterinary Pathology
2021, volume: 58, number: 2, pages: 243-257

Authors' information

Donovan, Taryn A.
Animal Medical Center of New York
Moore, Frances M.
Heska Corp
Bertram, Christof A.
Free University of Berlin
Luong, Richard
Bolfa, Pompei
Ross University School of Veterinary Medicine
Klopfleisch, Robert
Free University of Berlin
Swedish University of Agricultural Sciences, University Animal Hospital
Salas, Elisa N.
No organisation
Whitley, Derick B.
Antech Diagnost
Aubreville, Marc
Tech Hsch Ingolstadt
Meuten, Donald J.
University of North Carolina

Sustainable Development Goals

SDG3 Good health and wellbeing

UKÄ Subject classification

Clinical Science

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