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Kidney tumor

Adult malignancies - miscellaneous

Nuclear grading (Fuhrman)


Reviewers: Sean Williamson, M.D. (see Reviewers page)
Revised: 13 July 2012, last major update July 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General
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● Based on most malignant features in one high power field (Am J Surg Pathol 1982;6:655)
● The high-power field with greatest degree of nucleolar prominence is recommended as the main basis for grading (Am J Surg Pathol 2011;35:1134)
● Note: every cell need not show the criteria, but if most cells in one high power field show a higher grade, that grade should be used

Fuhrman (nuclear) grade:
1 - Small, round, uniform nuclei (10 microns), inconspicuous nucleoli, look like lymphocytes (very rare)
2 - Slightly irregular nuclei, see nucleoli at 40x only, nuclear diameter 15 microns, open chromatin [40% of tumors]
3 - See nucleoli at 10x, nuclei very irregular, diameter 20 microns, open chromatin [30-40% of tumors]
4 - Mitoses; bizarre, multilobated, pleomorphic cells plus grade 3 features, macronucleoli [15% of tumors]

● Moderate intra- and interobserver agreement is improved to substantial agreement if collapse to 2 categories of grades 1/2 and 3/4 (Arch Pathol Lab Med 2003;127:593, Cancer 2005;103:625) or 3 categories (Cancer 2005;103:68)

Chromophobe carcinoma:
● Typical Fuhrman grading may not have prognostic significance (Am J Surg Pathol 2007;31:957)
● Alternative methods of grading have been proposed, such as:
(A) Exclusion of the pleomorphic, irregular nuclei with smudged or unclear nuclear chromatin and no nucleoli (likely degenerative in nature) and grading on remainder of the cells using the 4-tiered system (Am J Surg Pathol 2011;35:962)
(B) A unique chromophobe tumor grading system: 1) without nuclear crowding and anaplasia, 2) nuclear crowding (touching nuclei) and size variation > 3 fold or 3) presence of frank anaplasia (nuclear polylobation or tumor giant cells, again excluding degenerative changes, Am J Surg Pathol 2010;34:1233) suggested to have higher predictive accuracy (J Urol 2011;186:2168)

Papillary carcinoma:
● One study regarding papillary carcinoma recommends assessing nucleolar prominence based upon high power field with greatest nuclear pleomorphism (Am J Surg Pathol 2006;30:1091)

Micro images
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Grade 1 nuclei are regular with indistinct nucleoli

   
Grade 2 nuclei have irregular contours and nucleoli present at 40x

   
Grade 3 nuclei have more irregular contours and nucleoli present at 10x


Grade 4 nuclei

End of Kidney tumor > Adult malignancies - miscellaneous > Nuclear grading (Fuhrman)


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