#GUpath radical prostatectomy (for prostate ca, better seen elsewhere) here, nice example of CENTRAL ZONE (boxed) showing 🔬clear cell cribriform hyperplasia juxtaposed to 🔬HGPIN (outlined)

**Genetic promiscuity** Genetic fusions that once were thought to be entity-defining are now understood as one piece of information that pathologists use to get to a final diagnosis Clinical correlation, morphology, IHC, and sometimes methylation profiling help sort out these potentially confusing problems resulting from promiscuous fusion genes Dr. Folpe #USCAP2026 #pathology #PathX #PathTwitter

Answer to last wk's case: Uterine tumors resembling ovarian sex cord tumor (UTROSCT). UTROSCT is a mesenchymal uterine tumor consisting cells with architectural patterns resembling ovarian sex cord-stromal tumors without recognizable component of endometrial stromal neoplasia.

Sex cord-stromal markers Calretinin, SF-1, FOXL2, and inhibin SF-1 and FOXL2 IHC are highly sensitive for adult granulosa cell tumors (AGCT)/sex cord-stromal tumors (SCST) Calretinin and inhibin are neither specific nor sensitive for AGCT/SCST FOXL2 IHC is an SCST marker, including granulosa cell tumor. FOXL2 IHC is not the same as FOXL2 mutation status Dr. Howitt #USCAP2026 #pathology #PathX #PathTwitter

Invasive urothelial carcinoma with lipoid and micropapillary features — a frequent association worth recognizing. Lipid-filled cytoplasmic vacuoles alongside micropapillary clusters/retraction spaces make for a striking diagnostic image. #GUPath #UroPath

"Common things are common"; until they aren't. 17 Y/M, C/O pain abdomen. Colonoscopy: Colonic submucosal lesion & central ulceration. Microscopy never ceases to surprise. Differentials ❓ (IHC will follow) #PathTwitter #GIPath #CaseChallenge #Oncopath #PathResidents

Half of cellular blue nevus are S100 negative but SOX10 positive Potential pitfall and also a clue when evaluating these lesions Dr. Folpe #USCAP2026 #pathology #PathX #PathTwitter

Cytoplasmic Granules in Granular Cell Tumor & Congenital Epulis: A Histochemical & Immunohistochemical Note Aadithya Urs, Revathi Krishna, Lama Malik, J Augustine & Priya Kumar rdcu.be/fdSte #HeadNeckPathol #HNPJ #HeadandNeckPath #Pathology #ENTPath #PathologyTweet

#NeuroPath 42 years old female Decreased vision in right eye #PathX #Pathology #Pathresidents #Pathologists Which histologic variant of Meningioma?

Medullary thyroid carcinoma pathology #pathology

Not every “cancer” is cancer. IgG4-related disease can present as a hard mass in the salivary gland, pancreas, orbit, kidney, lung, and many other organs—often mimicking malignancy on imaging and clinically. Before calling it a tumor: sometimes the immune system is the culprit.

Frozen sections for sentinel lymph nodes after neoadjuvant chemotherapy (NACT) can be challenging In cN0 HER2 or TNBC patients post-NACT, positive SLNs are uncommon and frozen section sensitivity is modest Deferring SLN evaluation to final pathology is often reasonable, these findings support that approach ➡️ Frozen sections post-NACT are specific but not sensitive • Positive LN after NACT (pic 1) • Negative LN with biopsy/therapy-related changes (common pitfall: exuberant treatment effect can mimic carcinoma) Dr Gilmore #USCAP2026 #pathology #PathX #PathTwitter

From adaptor protein to oncogenic driver. A leucine-to-proline substitution at codon 265 (L265P) transforms MYD88 from a tightly regulated signalling adaptor into a constitutively active driver of lymphoma. The result? - Persistent NF-κB activation - Enhanced B-cell survival - Uncontrolled proliferation How does a single molecular alteration reshape an entire signalling network? Read the full Gene of the Month article to see how MYD88 became one of the most important biomarkers in lymphoid malignancies: bit.ly/4o94W5b

PDL1 IHC scoring guideline #PD1 #PDL1 #CTLA4 #HN #GEJ #NSCLC #TNBC #ASCO #IASLC #NCCN #FDA #WHO #NEET #NEETSS

What’s Hot in Pathology? We are honored that two papers from our esteemed collaborators have been selected as featured article in Hot Topics in Pathology by Lippincott Williams & Wilkins/Wolters Kluwer, published in The American Journal of Surgical Pathology and Advances in Anatomic Pathology. Congratulations to Dr. Anandi Lobo and Dr. Alessia Cimadamore for leading these outstanding studies, and to all co-authors for their invaluable contributions. Featured articles: ALK-Rearranged Renal Cell Carcinoma
The American Journal of Surgical Pathology
pubmed.ncbi.nlm.nih.gov/4179… Ductal Adenocarcinoma of the Prostate
Advances in Anatomic Pathology
pubmed.ncbi.nlm.nih.gov/4163…

BAGP Case of the Month 🔬 A tumour outside its natural habitat 👾 48-year-old woman with abdominal bloating, distension and generalised tenderness. Found to have ascites and elevated CA125 levels (148). Laparoscopy: Acute inflammation, small white nodule on left round ligament. Uterus, tubes and ovaries appeared normal. Biopsies taken from left round ligament, omentum and peritoneum. Omental biopsy histology below. Answers to follow next Friday! #BAGPCaseoftheMonth #BAGPCotM #GynaePath #GynPath #PathTwitter #PathQuiz

Cervical spinal lesion in a middle-aged woman. Diagnosis? (Feel free to snack on some CAPNON Crunch cereal while you're thinking about it.) #pathology #neuropath #PathTwitter

Gastric Xanthoma HE ▶️ CD163▶️ CK #GIpath #Pathology #PathTwitter #PathX

Before making a diagnosis of invasive breast cancer in a core needle biopsy, be sure it is truly a primary breast tumor, particularly in the era of neoadjuvant chemotherapy Metastatic serous carcinoma and metastatic melanoma to breast (pic 1) Metastatic lung adenocarcinoma (pic 2) Metastatic medullary thyroid carcinoma (pic3) Of 2423 TNBC submitted to Caris for molecular profiling over 19 months there was a misdiagnosis of TNBC in 73 cases (3%). Half of those cases were non-small lung cancer (data submitted for publication) Dr. Schnitt #USCAP2026 #pathology #PathX #PathTwitter

When do you work up a triple-negative cancer in a breast core needle biopsy to rule out metastasis? - When histologic features raise concern for non-breast origin, especially if there is no in situ carcinoma (sometimes this is a difficult distinction to make). - All triple-negative cancers unless there is in situ carcinoma. What stains do you do? GATA3 is performed by >90% of breast experts, followed by SOX10, CK, TRPS1, and TTF-1 (pic 2). Dr. Schnitt #USCAP2026 #pathology #PathX #PathTwitter