1. KCP 791 삼성서울병원 전공의 신유주

2. Patient history F/58 On chemotherapy (due to breast cancer) Carotid doppler ultrasound (follow up) –Thyroid nodule Ultrasonography –About 1.3cm sized irregular shaped mass at right thyroid mid pole posterior aspect Fine needle aspiration BRAF mutation test

12. Cellular Loosely cohesive, syncytial Small cell balls Atypical medium to large sized cells admixed with normal follicular cells High N/C ratio Slightly coarse chromatin pattern Inconspicuous nucleoli Nuclear grooves No definite intranuclear inclusions Vacuolated cytoplasm Focal dirty debris in background No mitosis Cytologic findings

13. Differential diagnosis

14. Metastatic tumor of thyroid gland Carcinoma of kidney, lung, breast, GI tract(colon); melanoma Clinical history of malignancy is key information Asymptomatic Three patterns of metastatic involvement –Multiple small but discrete foci of less than 2mm An admixture of malignant cells and benign follicular cells –A single discrete clinically palpable nodule –Diffuse widespread parenchymal involvement Tumor diathesis is frequent particularly in large tumors Features that favor metastasis (4) –The documented history of primary cancer –The presence of unremarkable thyroid follicular cells mixed with cancer cells –The functional differentiation of the cytoplasm of cancer cells –Characteristic cytomorphology of certain types of neoplasms Breast origin –single-fine chains of cells (caterpillars) –Intracytoplasmic lumens

15. Primary thyroid cancer PapillaryFollicularAnaplasticMedullary CellsUniformMonotonousSpindle/giantPlasmacytoid /spindle NucleiOvalRoundPleomorphicRound to spindle MembraneGroovedSmoothVery irregularSmooth Intranuclear inclusions >90% casesNoneCan occur50% cases ChromatinPowdery, paleGranularVery abnormalSalt & pepper NucleoliSmall, marginatedVariable, centralLargeSmall CytoplasmSquamoidDelicateVariableRed granules PapillaeCharacteristicAbsent Rare FolliclesCommonCharacteristicAbsentRare

16. Metastatic breast cancer Ductal adenocarcin oma Lobular carcinoma Medullary carcinoma Mucinous carcinoma Apocrine carcinoma Papillary carcinoma Tubular carcinoma CellularityVariable Highly Variable Low HighlyVariable HighlyVariable PresentationLoosely cohesive, syncytial Short chain, syncytial Loosely cohesive, syncytial Syncytial, papillary configuration Loosely cohesive, syncytial Central core Syncytial, tubular structure CellVariable High N/C Small, round High N/C Round High N/C Small to medium Uniform High N/C Medium to large High N/C VariableUniform High N/C NucleiVariable size Smooth to irregular membrane Macro- nucleoli Molding Pleomorphic Smooth to irregular membrane Prominent nucleoli Variable size Smooth membrane Large round Smooth to irregular membrane Smooth membrane Micro-nucleoli Uniform Smooth membrane Inconspicuou s nucleoli ChromatinFine to coarse Coarsely granular Fine to coarse Finely granular Coarsely granular Finely granular Fine to coarse CytoplasmVariableScant Secretory vacuoles VariableScant to moderate Vacuolated Abundant Bubbly Vacuolated Variable paleScant BackgroundNecrosis(HG) Cellular debris CleanLymphoid cells Abundant mucin Histiocytes Clean

17. Differential diagnosis KCP 791Primary thyroid cancer (PTC) Metastatic breast cancer PresentationLoosely cohesive, syncytial Papillary Loosely cohesive, syncytial NucleiMedium to large High N/C Variable size Variable N/C Variable size High N/C Chromatin patternSlightly coarsePale, dusty, powdery to finely granular Fine to coarsely granular Nuclear groove/inclusion Nuclear groovesIntranuclear inclusionsSmooth to irregular nuclear membrane CytoplasmVacuolatedVariable Pale Variable Can be vacuolated BackgroundFocal dirty debrisCleanNecrosis (HG) Cellular debris

20. Final diagnosis Metastatic carcinoma