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PSC Thyroid Guidelines Bill Faquin, M.D., Ph.D.

Diagnostic Terminology and criteria NonFollicular !esions "

Chronic lym#hocytic thyroiditisChronic lym#hocytic thyroiditisPrimary lym#homaPrimary lym#homa

Pa#illary thyroid carcinomaPa#illary thyroid carcinoma

$ndi%%erentiated carcinoma$ndi%%erentiated carcinoma

Medullary carcinomaMedullary carcinoma

Secondary tumorsSecondary tumors

Chronic !ym#hocytic Thyroiditis"Chronic !ym#hocytic Thyroiditis" First descri&ed in '(')

Most common %orm o% thyroiditis

Most common cause o% hy#othyroidism in the $.S.

*(+ #atients ha-e autoanti&odies

Cytologic Features o% Chronic !ym#hocytic Thyroiditis" Mied #o#ulation o% lym#hocytes and #lasma cells

!ym#hohistiocytic aggregates

Cohesi-e grou#s o% %ollicular cells /ith oncocytic %eatures

0aria&le nuclear aty#ia

Di%%erential Diagnosis o% Chronic !ym#hocytic Thyroiditis" Pa#illary thyroid carcinoma

1urthle cell neo#lasm

2eacti-e lym#h node

Primary lym#homa

Primary Thyroid !ym#homa" N1! accounts %or 34 o% #rimary thyroid neo#lasms5 ).4 o% etranodal

lym#homas

6+'++ arise in the setting o% 1ashimoto7s thyroiditis 8229:+;+##ro. 4+ #resent /ith a single dominant thyroid nodule

Derringer et al. 8>F?P< 8>@SP, )+++, ):"A)=A=(< '+; cases

); M>!T

== D!BC! M>!T

=; D!BC! only

' Follicle center lym#homa

1odgin lym#homa, #lasmactyoma, and Tcell lym#homas are -ery rare

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Marker studies such as flow cytometry are essential in the evaluation of

aspirates where there is a suspicion of lymphoma.

Pa#illary Thyroid Carcinoma"

$# to ;+ o% thyroid carcinomas

?ndolent 8although certain -ariants are aggressi-e< 3A.4mortality

May sho/ local in-asion and !N mets

oung to middleaged /omen

Prior radiation e#osure

FN> is highly accurate %or the diagnosis o% #a#illary carcinoma" *(+ are diagnosed as #ositi-e or sus#icious &y FN>

?n some studies, FN> is more accurate than %roEen section

False negati-e rate is lo/"o Cystic #a#illary carcinomas

o Follicular -ariant o% #a#illary carcinoma

o >dmiture o% &enign thyroid tissue

Diagnostic Cytologic Features o% Pa#illary Carcinoma"

nlarged, o-al nucleus /ith eccentric nucleolus

Fine, #ale chromatin

!ongitudinal nuclear groo-es

?ntranuclear #seudoinclusions>dditional Cytologic Features"

Pa#illary cytoarchitecture

Syncytial monolayers

Dense squamoid cyto#lasm

Bu&&legumH colloid

Psammoma &odies

Multinucleated giant cells

Ihat are the most diagnostic %eatures o% #a#illary carcinomaJ

Kini et al. 8'(;+

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Pa#illary structures /ithout -essels

?ntranuclear #seudoinclusionsMeta#lastic cyto#lasm

Basu et al. 8'(()na#lastic carcinoma

3 4 o% all thyroid malignancies

2a#idly %atal #rognosis local in%iltration8mean sur-i-al 9 A monthss