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Thymoma A: ATYPICAL/BIPHASIC? (1153804)
Thymoma A: ATYPICAL/BIPHASIC?new
Subtitle: B20-11974
Type:
THYMUS
Sender:
ugnius
2020-04-10 09:00
INCTR - EBMWG Hematopathology Online
CASE IS OPEN FOR DISCUSSION:  
 
81 yrs old female with history colorectal polyps (different kinds of adenomas NOT INCLUDED there) presented with mediastinal mass.  
Core biopsy was taken (included).  
After diagnosis of "thymoma A" the tumor was resected.  
MACRO: Greyish/white, fleshy, encapsulated tumor 9,5x9x4,5 cm.  
HISTO: Encapsulated nodules and diffuse zones: solid, trabecular, nested, NET like, focally spindled. 1 single nodule (block 10) and in part focal areas in another blocks are BIPHASIC:  
- epithelioid larger cells in nests;  
- in between more "lymphoid" or "blastic" or "immature" appearing still epithelial cells (PanCK+).  
Mitoses focally up to 8/10 HPF.  
IH: Predominantly PanCK+ CK5+ p63+ tumor, but still BIPHASIC in block 10 and small cells seems to be p40/p63/CK5(-) but PanCK+ (as histology pattern was).  
FULL: PanCK+; CK5/p63/p40+; Chromogranin A/Synaptophysin(-); CD5/CD117/S100/CD56(-); Ki67 heterogenous up to 30%.  
 
DIAGNOSIS: Thymoma A with multifocal microscopic transcapsular spread ((9,5 cm); pT1a; Masaoka-Koga IIb; minimal distance form margin <0,1mm).  
 
QUESTIONS:  
- Biphasic pattern in single thymoma nodule (but not B component- without blasts or lymphos);  
- High Ki67 index and focally visible mitotic activity: is it enough and more appropriate to call it "atypical thymoma A"?  
 
LINKS (the list):  
RESECTION:  
 
http://aperio.vpc.lt/imageserver/scan2/2020-04-10/B20-11974_2_HE_20x.svs/view.apml?  
 
http://aperio.vpc.lt/imageserver/scan2/2020-04-10/B20-11974_11_HE_20x.svs/view.apml?  
 
http://aperio.vpc.lt/imageserver/scan2/2020-04-10/B20-11974_7_HE_20x.svs/view.apml?  
 
http://aperio.vpc.lt/imageserver/scan2/2020-04-10/B20-11974_10_HE_20x.svs/view.apml?  
 
BIOPSY:  
 
http://aperio.vpc.lt/imageserver/scan2/2020-03-13/B20-9596_1_HE_20x.svs/view.apml?  
 
ThankYou and BeSafe. Happy (Private) Easter 2020.
Annotations » Add comment (Login)
tzankov
2020-04-14 15:57
Happy Easter, Ugnius!  
 
Thank you for the nice case. In my opinion - clear cut type A thymoma: everything fits - the clinical presentation, the macroscopy and the microscopy. The term atypical type A thymoma should be reserved for case with areas of necrosis and perceptible mitotic activity. KI67 should not be leading. I ma not sure, but please look once again at the TNM manual, if pT1a (or be if pleural invasive) would not be better fitting, since pT2 = pericardial invasion!  
 
Kind regards  
 
Alex
ugnius
2020-04-14 16:13
Thanx, Alex. My bad (mean TNM).
ugnius
2020-07-15 12:03
Last modified: 2020-07-16 11:06:47