Two signet rings, which one is malignant?.#CytoPath #PathTwitter #Pathology.🙏

✅ BRAF. The majority of SSL are driven by a BRAF V600E mutation. This is a hallmark of the serrated neoplasia pathway and distinguishes them from most conventional adenomas and many TSAs .#PathTwitter #Pathology #GIPath

✅ Sessile Serrated Lesion. SSLs are important precursors to colorectal cancer via the serrated pathway. Key features include:.- Serration extending to the crypt base. - Architectural distortion of crypt bases: dilation, horizontal growth along the muscularis mucosae, forming "L"

❌ Tubular Adenoma.Tubular adenomas are defined by cytologic dysplasia (enlarged, hyperchromatic, pencillate nuclei) in tubular glands. They lack the serrated architecture seen in HPs, SSL, and TSAs.

❌ Traditional Serrated Adenoma (TSA).TSAs are another serrated precursor, but they are characterized by tall columnar cells with eosinophilic cytoplasm, pencillate nuclei, and complex villous or papillary architecture with ectopic crypts. They are also more common in the left

❌ Hyperplastic Polyp.Hyperplastic polyps (HPs) also show serrated architecture, but it's typically confined to the upper half of the crypts. The crypt bases remain straight and narrow, and the proliferative zone is restricted to the base, unlike the architectural distortion seen

What is the most characteristic gene mutation?.

The key is the abnormal crypt architecture at the base (classic "boot-shaped" crypts). What is the most characteristic gene mutation?. A) APC.B) STK11.C) KRAS.D) BRAF.#PathTwitter #Pathology #GIPath.WSI

What's the diagnosis?.

Flat, 8mm polyp in the ascending colon. What's the diagnosis?. A) Sessile Serrated Lesion (SSL).B) Hyperplastic Polyp.C) Traditional Serrated Adenoma (TSA).D) Tubular Adenoma.#PathTwitter #Pathology #GIPath. WSI

Activating mutations in the CTNNB1 gene (encoding beta-catenin) are present in >90% of SPNs. This leads to the nuclear accumulation of beta-catenin. #PathTwitter #Pathology #GIPath.

✅ Solid Pseudopapillary Neoplasm (SPN).SPN is a low-grade malignant tumor typically affecting young women. Histologically, it's defined by sheets of uniform cells with characteristic nuclear grooves that form pseudopapillae around fibrovascular cores due to cellular discohesion.

❌ Serous Cystadenoma.This is a benign cystic neoplasm composed of numerous small cysts lined by glycogen-rich, clear cuboidal cells. It lacks the solid growth and pseudopapillary features of an SPN.

❌ Acinar Cell Carcinoma.Acinar Cell Carcinomas show acinar differentiation with cells containing abundant granular eosinophilic cytoplasm (zymogen granules) and prominent nucleoli. They are positive for acinar markers like Trypsin and Chymotrypsin.

❌ Pancreatic Neuroendocrine Tumor (PanNET).PanNETs can have solid or nested growth, but their cells have characteristic "salt-and-pepper" chromatin and are diffusely positive for neuroendocrine markers like Synaptophysin and Chromogranin A. They lack the pseudopapillary

What is the characteristic IHC finding for this tumor?. A) Positive Synaptophysin.B) Positive Trypsin.C) Nuclear Beta-Catenin.D) Loss of L-FABP.

The classic demographic (young woman) and histology point to Solid Pseudopapillary Neoplasm (SPN). The pseudopapillae form as poorly cohesive cells fall away from fibrovascular cores. #PathTwitter #Pathology #GIPath

What's the most likely diagnosis?.

28F with a large, well-demarcated mass in the tail of the pancreas. What's the most likely diagnosis?. A) Solid Pseudopapillary Neoplasm (SPN).B) Pancreatic Neuroendocrine Tumor (PanNET).C) Acinar Cell Carcinoma.D) Serous Cystadenoma.#PathTwitter #Pathology #GIPath #PancreasPath

RT @slusagar: #GUpath: 30ish male with testicular mass. Dx: Epidermoid cyst

✅ Perineurioma. This benign polyp is composed of bland spindle cells with perineurial differentiation, which characteristically entrap colonic crypts and arrange in a concentric, "onion-skin" pattern within the lamina propria. Perineurial cells are positive for Epithelial