No tricks here. What category would everyone use for this thyroid FNA, and why?

Horrible treatment (radiation) associated epithelial changes in duodenal mucosa. The p53 can be ignored, probably reflecting upregulation rather thana mutational event. The same can be seen in the stomach. Hutchings DA, et al PMID: 36843539; PMCID: PMC10460459.

Mastocytosis (seen here) is often sought by naive colleagues and seldom seen. Mod Pathol offers a great review: Panarelli NC, Hornick JL, Yantiss RK. What Is the Value of Counting Mast Cells in Gastrointestinal Mucosal Biopsies? Mod Pathol. 2023 Feb;36(2):100005. PMID: 36853780.

Our Gynecologic Pathology cases @UMiamiPathology are fascinating! Here’s a striking example of pilomatrix-like high-grade endometrial carcinoma (PiMHEC), a recently described entity mostly driven by CTNNB1 mutations. Look for solid basaloid growth with conspicuous central tumor cell necrosis, and pilomatrix-like keratinization with the hallmark ghost cells. This case also had a focal conventional FIGO grade 1 endometrioid component. IHC shows diffuse nuclear β-catenin with loss of PAX8 and ER in the pilomatrix-like component. These tumors are believed to behave aggressively.

1/ Necrosis = cell death (unlike apoptosis, it does not occur naturally and is not programmed) This short #Tweetorial shows you some of the histologic flavors of necrosis. The stain in each of these pics is hematoxylin-eosin (H&E) #pathology #pulmpath #pathtweetorial

Fact or artifact? 😰 Poor Fixation 🔬 Underfixation can make perfectly benign TDLUs look discohesive and atypical, mimicking atypical lobular hyperplasia (ALH). #PathX #PathTwitter #breasthpath

Not all that has ink is a true margin. 1. Make sure the ink is not in a cleft between fat lobules 2. Make sure you have a full cross-section of the tissue in the block. Tissue disruptions with ink are to be considered artifactual until proven otherwise 3. Check the diagram that shows where the section was taken from 4. If in doubt, walk over to the histology and lab and ask for the paraffin block. Looking at the entirety of the tissue within the block will give you information you cannot easily glean from the two-dimensional slide #breastpath

40 year old with a skin mass above sternum, R/O lipoma. Herniated lung??? probably not :)

New thread: is it consistent with sarcoidosis? 1/ Yes!

Asteroid body in a foreign body mutinucleated giant cell. This is an axillary LB biopsy from a patient w/ breast implant #pathresidents #pathX

An example of crystal storing histiocytosis; the patient needs to be evaluated for a plasma cell disorder or other lambda-restricted B cell neoplasm. Arnold CA, et al. Am J Surg Pathol. 2018 Oct;42(10):1317-1324. PMID: 29878935.

Appendix

If you submitted all the appendix and you don't see epithelium, just mucin in the lumen, sign it as: -Dilated appendix with mucin Comment: The differential includes LAMN or reactive processes Dr. Umetsu #CAP23 #everydayGI #GIpath #PathX #PathTwitter #pathology #pathologists

Appendix Postinflammatory mucosal hyperplasia -Associated with acute/interval appendicitis -Epithelium looks hyperplastic/serrated near surface -This is not LAMN ⚠️ #surgpath #pathology #PathTwitter #GIpath CAP today digital.olivesoftware.com/ol… Thanks for sharing @Voltaggiol 🌟

Challenges of staging appendiceal mucinous neoplasms Mucin outside the appendix in a LAMN case, is it pT4 or not? -Acellular mucin without inflammatory reaction, mesothelial hyperplasia, or neovascularization is presumed to be a result of carryover during handling or gross examination, and should not be designated as pT4a (Pic A) - Organizing acellular mucin with neovascularization on the serosal surface is categorized as pT4a (Pic B) Umetsu et al doi.org/10.1016/j.humpath.20…

When large nests of tumor surround a completely normal duct, they are much more likely to be invasive cancer or lymphovascular invasion than DCIS. A useful pattern to remember on a biopsy #breastpath

#GUpath prostate bx: Gleason score 3 4, with pattern 4 comprised of glomerulation and poorly formed glands

Pagetoid Spread of ALH ⛏️👷‍♂️🔬 Dyshesive atypical lobular cells undermining and spreading along the undersurface of the ductal epithelium in a pagetoid pattern—subtle and may mimic myoepthelial cell hyperplasia. #PathX #PathTwitter #breastpath

Pagetoid Spread of DCIS ⛏️👷‍♂️🔬 Atypical ductal epithelial cells undermining the ductal epithelium of large ducts in a pagetoid distribution. #PathX #PathTwitter #breastpath