🔬 A Cytology Lesson: One Marker • Two Histories • Three Primaries !!! 👩‍⚕️ Patient • 72-year-old female with pleural effusion • Initial history provided: Previous h/o anal squamous cell carcinoma and breast carcinoma 🔍 Cytology Findings • Highly cellular specimen • Malignant epithelial cells in clusters and 3D groups • Marked nuclear atypia • Occasional vacuolated cytoplasm 🧪 Initial Cell Block IHC ✅ BerEP4 positive ❌ Calretinin negative ✅ CK7 positive ❌ CK20 negative 🎯 Diagnostic Approach Based on Available History • TTF1 → to exclude primary lung adenocarcinoma • p63 → to assess squamous differentiation • TRPS1 → to evaluate possible breast origin 📋 Results ❌ TTF1 negative ❌ p63 negative ✅ TRPS1 patchy positive ⚠️ The Pitfall With a history of breast carcinoma and a CK7 /TRPS1 profile, metastatic breast carcinoma seemed highly likely. 🔄 The Turning Point • TRPS1 positivity was only patchy • Additional clinical information was obtained • Histologic correlation was performed 🧩 The Missing History The patient also had a recently diagnosed endometrial malignancy with frozen pelvis and extensive local spread, a crucial piece of information that was not initially available. 🧬 Further Workup ✅ PAX8 positive - favor mullerian ❌ GATA3 negative - point against breast cancer 📌 Final Interpretation Metastatic Müllerian carcinoma, with correlation favoring high-grade serous carcinoma. 💡 Take-Home Messages ✔️ TRPS1 is a useful marker, but not entirely specific for breast carcinoma. ✔️ Patchy TRPS1 positivity can be seen in Müllerian serous carcinomas and other non-mammary tumors. ✔️ Never interpret immunostains in isolation. ✔️ Morphology Clinical History Imaging Histology Correlation = Accurate Diagnosis. ✔️ Always question a result that does not perfectly fit the overall picture. 🏆 Lesson Learned 💎 The most important diagnostic tool in this case was not TRPS1—it was the missing clinical history. #Cytopathology #PleuralFluid #DiagnosticPitfall #TRPS1 #BreastPathology #PathologyPearls #Cytology #ClinicopathologicCorrelation #PathTwitter #MedEd #LearningFromCases

👉 74-year-old female with hematuria and bladder mass ⚓️ Urine cytology showed features suspicious for High-Grade Urothelial Carcinoma (HGUC) with: 🔬 Hyperchromatic crowded cell clusters 🔬 Single scattered atypical cells 🔬 Marked pleomorphism, high N:C ratio 🔬 Irregular nuclear membranes & coarse chromatin 💎 Biopsy confirmed High-Grade Papillary Urothelial Carcinoma showing fused/complex papillae, loss of maturation, diffuse cytologic atypia, and numerous mitoses. A nice histocytologic correlation case highlighting the importance of urine cytology in detecting HGUC. #PathTwitter #Cytopathology #Uropath #Surgpath #UrineCytology #HGUC #UrothelialCarcinoma #Histopathology #MedEd #Pathology

💎 Solitary Fibrous Tumor (SFT) involving the submandibular gland.   🔍  58-year-old male with a 5.5 cm left submandibular gland mass.   ⚓️ Grossly, the lesion was a well-circumscribed, fleshy, firm white-tan mass with a solid whorled cut surface.   🔬 Microscopy showed a bland spindle cell neoplasm arranged in a “patternless pattern” with alternating hypo- and hypercellular areas, dense collagenized stroma, and prominent branching/staghorn-like vessels. Tumor cells showed minimal atypia and low mitotic activity.   🧪 IHC profile: • STAT6 nuclear positive •.CD34: diffuse positive • PanCK & S100: negative • SMA / Desmin: highlighted only vessel walls, negative in tumor cells • Beta-catenin: cytoplasmic granular staining without nuclear positivity   💡 Key points: • SFT is a rare mesenchymal neoplasm in salivary glands, most commonly affecting the submandibular gland and parotid. • The characteristic molecular alteration is the NAB2::STAT6 fusion, resulting from inversion at chromosome 12q13 and leading to nuclear STAT6 expression which is highly sensitive and specific for SFT. • Most SFTs behave indolently, but risk stratification depends on factors such as size, mitotic activity, necrosis, and patient age. Rare cases may recur or metastasize.   📚 Important morphologic clues favoring SFT: ✔ Patternless architecture ✔ Ropey collagen ✔ Staghorn vasculature ✔ Bland spindle cells ✔ Diffuse CD34 positivity & nuclear STAT6 positivity Case courtesy @annsmiley78   #PathTwitter #SurgPath #HeadNeckPath #SalivaryGlandPathology #SoftTissuePathology #SolitaryFibrousTumor #SubmandibularGland #Histopathology #Pathology #MedEd

Pleural fluid CYTOLOGY. 📌 Clinical: Male patient with known urothelial carcinoma of bladder with metastases to lung, chest wall, and bone, presenting with pleural effusion. 🔬 Cytology (Pap & DQ): •Moderate cellularity •Clusters and sheets of atypical epithelial cells in a hemorrhagic background •Cells show high N:C ratio, nuclear irregularity, coarse chromatin, and prominent nucleoli •No definite gland formation 🧫 Cell block: •Cohesive clusters of malignant epithelial cells with similar morphology 🧪 IHC: •BerEP4 , CK7 •GATA3 , p63 •CK20: focal weak •Calretinin– (excludes mesothelial origin)   🔹 Diagnosis: Malignant effusion – metastatic carcinoma consistent with urothelial origin   🔹 Teaching points 💡 ✔️ GATA3 p63 co-expression → strong clue to urothelial carcinoma ✔️ In pleural effusion, always differentiate from lung adenocarcinoma & squamous carcinoma ✔️ BerEP4 / Calretinin –ve → epithelial, not mesothelial ✔️ CK20 may be variable/focal in urothelial carcinoma   #PathTwitter #Cytopathology #PleuralFluid #EffusionCytology #UrothelialCarcinoma #MetastaticCarcinoma #DiagnosticPathology