David Alrahwan MD

🧵 1/9 Elderly male. Metastatic colorectal cancer with liver mets. RAS wild-type — looks straightforward. Then the molecular profile comes back: HER2 IHC 3+. This changes the entire treatment plan. Here's why 👇

Colon, 70y #pathology #patologia #gipath #gipathology

Triple negative basal-like breast cancers can be "pseudopapillary" Dr. Allison #USCAP2026 #pathology #PathX #PathTwitter #everydaybreastpath

*Microcystic Stromal Tumor (MST) of the ovary* Usually benign neoplasm with a classic triad: microcysts, solid cellular areas, and fibrous stroma. IHC: Nuclear β-catenin, cyclin D1, WT1, and SF1 positivity Key genetics: Mutually exclusive CTNNB1 or (less commonly) APC mutations → Rarely, MST is an extracolonic manifestation of familial adenomatous polyposis (FAP) and can serve as a sentinel event leading to the diagnosis of FAP Dr. Parra Herran #USCAP2026 #pathology #PathX #pathtwitter

A needle biopsy of this pancreatic solid pseudopapillary neoplasm was labeled "gastric mass". We initially tried to make it into a neuroendocrine tumor.... Sometimes needle placement is misleading.. LEF1 is a nice clean nuclear stain and easier to interpret than beta catenin.

41yo F, left partial nephrectomy → TFE3-rearranged RCC. Solid-papillary architecture + psammoma bodies. +expression of melanocytic marker HMB45. @IntSocUropath @GU_Path_Society #GUpath

Corded & Hyalinized Endometrioid Carcinoma (CHEC) • Usually associated with low-grade endometrioid carcinoma • CHEC component shows nuclear β-catenin staining • Most commonly misdiagnosed as carcinosarcoma β-catenin IHC tip: Ideal pattern (strong/diffuse nuclear, pic 2) Real-life pattern (highlights scattered nuclei, not every single one, pic 2) Dr. Joehlin / Dr. McGregor - Short course #USCAP2026 #pathology #PathX #PathTwitter

#PathQuiz 🔬 ______ fusion A) ASPSCR1::TFE3 B) WWTR1::CAMTA1 C) FUS::DDIT3 D) HEY1::NCOA2 #Pathology #SoftTissuePath #MolecularPath Clue in caption 🧐

Rapid flashcards for lung fungi Histoplasma, Cryptococcus, Coccidioides, and Blastomyces Dr. Mukhopadhyay – Pathology in The Coast 2025, CAP On Demand #pathology #pathX #pathtwitter

This gastric body biopsy shows severe destructive gastropathy - the parietal cells are gone! It is too inflamed for autoimmune gastritis/pernicious anemia. Apoptotic bodies, usually scarce in the stomach, are indicated. This was a result of pembrolizumab immunotherapy.

CD34 lattice-like / fingerprint pattern in neurofibromas CD34 (left pic) H&E (right pic) #pathology #PathX #Breastpath #PathTwitter

New in #HumPathol: Epstein-Barr Virus Associated Gastric Carcinoma: A Clinicopathologic Study with Recognition of a Distinctive Reticular Histologic Pattern. sciencedirect.com/science/articl… #pathology #PathTwitter #PathX #GIpath

A never-ending obsession with pyloric gland adenomas is a benign problem. This one arose in otherwise normal gastric oxyntic mucosa and coats the surface! They are also associated with autoimmune gastritis and probably arise from pseudo-pyloric metaplasia in that setting.

30s M with a renal mass. Diagnosis? #PathTwitter @MGBpathology @MGHPathology

Unusual case on TURP (stain is NKX3.1) Diagnosis in the comment 👇 #gupath #pathology #pathres #raretumor

Alveolar soft part sarcoma of the breast is quite rare but when it is encountered, one must consider a metastasis (such as from the extremity). innovativesciencepress.com Refs: PubMed PMIDs: 15735860, 18501064, 19021216, 23263847, 30832622

New in #HumPathol: Metastatic Thyroid-Like Follicular Renal Cell Carcinoma With EWSR1::PATZ1 Fusion: A Case Report and Review of the Literature. sciencedirect.com/science/articl… #pathology #PathTwitter #PathX #GUpath

Gulp! Apparently there is an eosinophilic variant of ‘mesenteric inflammatory veno-occlusive disease’ (MIVOD), also known as ‘enterocolic lymphocytic phlebitis’.

Breast ➡️ Pagetoid spread of lobular neoplasia 📌Luminal cells IHC: E-cadherin neg/p120 positive (cytoplasm) #breastpath #everydaybreast #pathology #PathResident #pathfellow #PathTwitter

@nalperenyldrm Great thought! However, Sertoli cell tumors typically show tubular, cord, or trabecular patterns, often with intersecting fibrous bands, and are usually negative for S100 and SMA. x.com/TingZhaoPathdo…