1. KCP-771 ( 제출자 ) 원자력병원 R3 허일영

2. History  71 세 여자환자  6 개월 전부터 운동시 호흡곤란  2 주일 전부터 호흡곤란이 악화  흉부단순촬영에서 오른쪽 폐에 흉수와 무기폐

6. Cytologic features  Clusters: many, large or >50 cells  Single population  Lacy, smooth & knobby cluster border  Papillary cluster Distinct nucleoli Round or oval nucleus Central nucleus position Fine or coarse chromatin Homogenous dense cytoplasm Slightly increased N/C ratio

7. Differential diagnosis  Reactive mesothelial hyperplasia (RMH)  Malignant mesothelioma (MM)  Metastatic adenocarcinoma (ADC)

8. Adv Anat Pathol 2006;13:174–184 Morphologic Criteria Still uncertainNot mesothelialMesothelial Immunohistochemistry (IHC) PATTERN RECOGNITION History of cancer? Check age, gender, effusion site. Need site-specific IHC Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. SIGN-OUT AS REACTIVE MESOTHELIAL CELLS (And describe any other cell mixture present) INDICATE THE POSSIBILITY OF MESOTHELIOMA Need tissue confirmation

9. Adv Anat Pathol 2006;13:174–184 Morphologic Criteria Still uncertainNot mesothelialMesothelial Immunohistochemistry (IHC) PATTERN RECOGNITION History of cancer? Check age, gender, effusion site. Need site-specific IHC Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. SIGN-OUT AS REACTIVE MESOTHELIAL CELLS (And describe any other cell mixture present) INDICATE THE POSSIBILITY OF MESOTHELIOMA Need tissue confirmation

10. Reactive mesothelial cellsMesotheliomaMetastatic adenocarcinoma PopulationSingle population Usually dual population ClustersFewManyVarying from few to many Clusters sizeSmall, <12 cellsVery large, >50 cellsLarge, >12 cells Clusters borderKnobby, scalloped Smooth CytoplasmTwo-tone Homogeneous uniform "Lacy skirt"Present Unusual N/C ratioMostly lowVaries from low to highMostly high Nucleus positionUsually central or paracentral Usually eccentric Nuclear shapeRound or ovalLess pleomorphic than ADCIrregular Nuclear membraneThin, smoothThick ChromatinDelicate, pale, clumped or darkHyperchromaticCoarse NucleoliCan be largeLarge Mitotic figuresMay be present Reactive mesothelial cellsMesotheliomaMetastatic adenocarcinoma PopulationSingle population Usually dual population ClustersFewManyVarying from few to many Clusters sizeSmall, <12 cellsVery large, >50 cellsLarge, >12 cells Clusters borderKnobby, scalloped Smooth CytoplasmTwo-tone Homogeneous uniform "Lacy skirt"Present Unusual N/C ratioMostly lowVaries from low to highMostly high Nucleus positionUsually central or paracentral Usually eccentric Nuclear shapeRound or ovalLess pleomorphic than ADCIrregular Nuclear membraneThin, smoothThick ChromatinDelicate, pale, clumped or darkHyperchromaticCoarse NucleoliCan be largeLarge Mitotic figuresMay be present Reactive mesothelial cellsMesotheliomaMetastatic adenocarcinoma PopulationSingle population Usually dual population ClustersFewManyVarying from few to many Clusters sizeSmall, <12 cellsVery large, >50 cellsLarge, >12 cells Clusters borderKnobby, scalloped Smooth CytoplasmTwo-tone Homogeneous uniform "Lacy skirt"Present Unusual N/C ratioMostly lowVaries from low to highMostly high Nucleus positionUsually central or paracentral Usually eccentric Nuclear shapeRound or ovalLess pleomorphic than ADCIrregular Nuclear membraneThin, smoothThick ChromatinDelicate, pale, clumped or darkHyperchromaticCoarse NucleoliCan be largeLarge Mitotic figuresMay be present Adv Anat Pathol 2006;13:174–184

11. HBME-1 H&E CK5/6 TTF-1

12. Adv Anat Pathol 2006;13:174–184 Morphologic Criteria Still uncertainNot mesothelial Mesothelial Immunohistochemistry (IHC) PATTERN RECOGNITION History of cancer? Check age, gender, effusion site. Need site-specific IHC Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. SIGN-OUT AS REACTIVE MESOTHELIAL CELLS (And describe any other cell mixture present) INDICATE THE POSSIBILITY OF MESOTHELIOMA Need tissue confirmation

13. Adv Anat Pathol 2006;13:174–184 Morphologic Criteria Still uncertainNot mesothelial Mesothelial Immunohistochemistry (IHC) PATTERN RECOGNITION History of cancer? Check age, gender, effusion site. Need site-specific IHC Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. Any concern for mesothelioma? Radiologic or clinical info., clusters very large, cells are atypical, etc. SIGN-OUT AS REACTIVE MESOTHELIAL CELLS (And describe any other cell mixture present) INDICATE THE POSSIBILITY OF MESOTHELIOMA Need tissue confirmation INDICATE THE POSSIBILITY OF MESOTHELIOMA Need tissue confirmation

14. Pleural fluid, cytology, ThinPrep Test : Atypical mesothelial cells Note> Reactive mesothelial cells 과 malignant mesothelioma 가능성이 있습니다.

17. Pleura, right, biopsy: Malignant mesothelioma, epithelioid type

18. PatternMost common diagnoses/Primary sites Papillary groups Ovary, mesothelial hyperplasia, mesothelioma, colon, lung, renal cell carcinoma, thyroid, pancreatobilliary, urothelial carcinoma, embryonal carcinoma Psammoma bodiesOvary, mesothelial hyperplasia, mesothelioma, thyroid, endosalpingiosis CannonballsBreast, lung, ovary, mesothelial hyperplasia, mesothelioma Acinar groups Lung, colon, ovary, mesothelial hyperplasia, mesothelioma, stomach, breast, endometriosis/ endosalpingiosis, renal cell carcinoma, pancreatobiliary, prostate Single large cells Reactive mesothelial cells, mesothelioma, squamous cell carcinoma of lung, melanoma, poorly differentiated adenocarcinoma, renal cell carcinoma, adrenal cortical carcinoma, hepatocellular carcinoma, germ cell tumors, sarcoma Adv Anat Pathol 2006;13:174–184 Pattern Most common diagnoses/Primary sites Papillary groups Ovary, mesothelial hyperplasia, mesothelioma, colon, lung, renal cell carcinoma, thyroid, pancreatobilliary, urothelial carcinoma, embryonal carcinoma Psammoma bodiesOvary, mesothelial hyperplasia, mesothelioma, thyroid, endosalpingiosis CannonballsBreast, lung, ovary, mesothelial hyperplasia, mesothelioma Acinar groups Lung, colon, ovary, mesothelial hyperplasia, mesothelioma, stomach, breast, endometriosis/ endosalpingiosis, renal cell carcinoma, pancreatobiliary, prostate Single large cells Reactive mesothelial cells, mesothelioma, squamous cell carcinoma of lung, melanoma, poorly differentiated adenocarcinoma, renal cell carcinoma, adrenal cortical carcinoma, hepatocellular carcinoma, germ cell tumors, sarcoma KCP-771

19. Classic Malignant Features 1.Pleomorphism, high N/C ratios, hyperchromasia, prominent nucleoli, and mitoses 2.Subtle or absent in well-differentiated MM 3.Benign proliferations are commonly atypical Syed Z. Ali, Edmund S. Cibas. Serous cavity fluid and cerebrospinal fluid cytopathology. Springer, 2012; 35-75.

20. Size & Number 1.Large cell clusters should suggest the possibility of malignancy such as MM or ADC 2.Numerous relatively large (>50 cells) balls of cells with berrylike external contours Arch Pathol Lab Med. 2012 Aug 28. [Epub ahead of print] Adv Anat Pathol 2006;13:174–184

21. 감사합니다.