Brian McMillen MD

#GIpath #Foodpath Let’s chop up some cauliflower, and maybe learn something about colon polyps in the process. @TxicMegacolon @CArnold_GI @ALBoothMD @TheKarenPinto @JMGardnerMD @Dr_Brian_Cox @DrGeeONE @AyeshaFarooqMD @Voltaggiol @LizMontgomeryMD

New study published in the May 2026 issue of Histopathology @Histo_Journal Congratulations to Drs. Shilpy Jha, @LoboAnandi and colleagues on this amazing paper investigating the molecular landscape of clear cell adenocarcinoma (CCA) of the urinary bladder, one of the rarest and least understood genitourinary malignancies. This important multicenter collaboration advances our understanding of a rare bladder cancer subtype and provides a foundation for future biologic and therapeutic investigations. In one of the largest series of bladder CCA, the authors identified recurrent alterations involving the PI3K/AKT/mTOR signaling pathway, particularly activating PIK3CA mutations (74%) and KRAS mutations (26%). Additional alterations involving SMAD4, RB1, ERBB2, TP53, MET, and APC further highlight the complex molecular architecture of this aggressive neoplasm. These findings provide important insights into tumor pathogenesis and identify potentially actionable therapeutic targets. Particularly noteworthy is the relatively high frequency of KRAS mutations in CCA, especially in light of the landmark Phase 3 RASolute 302 trial, published on May 31, 2026 in  New England Journal of Medicine (PMID: 42223072), which demonstrated remarkable efficacy of daraxonrasib, a pan-RAS (multi-selective) inhibitor, in patients with previously treated metastatic pancreatic cancer. These results provide compelling clinical evidence that RAS-driven tumors may be effectively targeted with next-generation therapeutics. Although clear cell adenocarcinoma of the urinary bladder remains an exceptionally rare malignancy, the finding that more than one-quarter of cases harbor KRAS alterations raises the intriguing possibility that a subset of patients could benefit from emerging RAS-directed therapeutic strategies. More broadly, these findings underscore the importance of comprehensive molecular profiling in rare genitourinary tumors, both to improve our understanding of tumor biology and to identify potentially actionable targets that may expand treatment options in the era of precision oncology. Full article available: pubmed.ncbi.nlm.nih.gov/41537408/

Happy Fathers Day to all the great Dads on #Pathtwitter/#PathX / everywhere!

Lung **Reactive pneumocytes vs malignant cells** Reactive - Spectrum of atypia - Cytoplasmic vacuolization - Maintained N/C ratios - Cytology: Napoleon hat sign Dr. Sauter #USCAP2026 #pathology #PathX #PathTwitter

#Surgpath #Pathresidents #Pathtwitter A human of indeterminate age and health status presents to a local clinic with a mass in one of his or her bodily organs, which is excised. #Pathresidents: Diagnosis? Benign? Malignant?

@IHC_guy Hope you brought cash! (I find their chicken and cheese better than the cheesesteak, is this considered heresy?)

You know I’m always game …

What’s hiding in the sentinel node? 🕵️‍♂️🔬 Let’s review some findings encountered in sentinel lymph nodes this week! Isolated Tumor Cells 🔬 Single tumor cells or small clusters, measuring ≤0.2 mm or <200 cells, require diligence to detect. #PathX #PathTwitter #breastpath

30s M, testicular mass. Diagnosis? #PathX #PathTwitter @MGBpathology @MGHPathology

@Andres_Matoso @ZMaleki_cyto Thank you for sharing this, @Andres_Matoso. Looks quite distinct from fibroepithelial polyps at other sites! #BeautyinB9

Fibroepithelial polyp at the bladder neck — a rare benign lesion characterized by anastomosing cystitis cystica, intermixed with loose fibrovascular stroma. Recognition is important, as it may mimic more concerning pathology. #Uropathology #Bladder

🧩 Bladder riddle Inspired by the previous post… Here is another spindle cell neoplasm. 🤔 Bland-looking spindle cells with eosinophilic cytoplasm, oval nuclei, and small round nucleoli. What would be your diagnosis? #DxMindMap #GUPath #BladderPath #PathTwitter @JHUpath

@garreyf @smlungpathguy @slusagar Thank you for asking this, @garreyf - I have often wondered about this. Ie, Helpful to report, or just more “data overload” for the clinicians. Also TY @slusagar for your guidance!

Prostate apex core needle biopsy. Does this finding require a more careful apical dissection if a radical prostatectomy is performed ? ie should we ever report? @slusagar

My pleasure. Last thought - please do not feel the need to apologize to us for sporadic content release. You are not letting us down. We (the “silent majority”, underrepresented on Twitter) get it. We are all going through similar shit. We just care about you, and hope you are doing well.

@Teclis82 Well, thanks compadre. I appreciate you deciding to listen.

I don't usually tell people this, but because we put out so few CS shows we have a lot of people out there who would like a new CS show,but never find out we've released one. If you know one of those people, I'd love it if you'd let them know.

#GUpath prostate: 3+4 with glomerulation? ✔️PIN4 #IHCpath occasionally HGPIN foci can mimic gloms

@LiangChengMD, we sincerely appreciate and applaud your tireless efforts in advancing #GUpath/#Urology practice - including this treasure trove of high yield, clinically impactful papers. We cannot wait to dig in and improve our practice! @AJSPjournal @IntSocUropath

🧩 Lost in the body maze Now I’m in the kid testis (epididymis) — but am I really in testis? 🤔 A forgotten embryology clue. What am I? #DxMindMap #Testispath #GUPath #PathTwitter @JHUpath

Corpora Amylacea ~ "Gems" 💎 #PathArt (A collage of more than 150 images collected from over 20 prostates) #GUpath #histology #pathology #PathTwitter #histology #BioArt #SciArt #microscopy #medicine #photography #MedEd

Congrats, @LiangChengMD! #GUpath

@ZemplenPataki @MAHoureih @UMichPath

Go ahead, sink your teeth into this one: Mandible. What is your diagnosis? 🔎 Poll below 🗳️👇 #PathPuzzle 🕵️‍♂️ @UMichPath #Pathology #PathX #PathTwitter

Congratulations, @LiangChengMD and colleagues! Looks like I’ve got something to read this weekend! @BrownPathology

@garreyf You got this 💪

Just received my 2 weeks notice #CapInspection